MftHBHi 
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LIBRARY 

OF   TMC 

UNIVERSITY  OF  CALIFORNIA. 


ARMATURE  WINDINGS 


OF 


ELECTRIC   MACHINES 


BY 

H.   F.    PARSHALL 

h 

MEMBER    AMERICAN   INSTITUTE    ELECTRICAL    ENGINEERS,   MEMBER    INSTITUTION    ELECTRICAL    ENGINEERS 
GREAT   BRITAIN,    MEMBER   AMERICAN   SOCIETY   OF   MECHANICAL    ENGINEERS,    ETC. 

AND 

I 


H.    M.    HOBART,   S.B. 


NEW  YORK 
D.  VAN    NOSTRAND    COMPANY 

LONDON 

ROBERT   W.    BLACKWELL 

39  VICTORIA  STREET,  WESTMINSTER 
1895 


of  raa 
UFI7IIRSIT7 


77C  •*' 
* 


Engineering 
Library 


COPYRIGHT,   1896, 
BY   D.   VAN  NOSTRANB  COMPANY. 


TYPOGRAPHY  BY  J.  S.  CUSHING  &  Co.v  NORWOOD,  MASS.,  U.S.A. 


TABLE  OP  CONTEXTS 
LIST  OF  DIAGRAMS    . 


UII7WSITY 


TABLE    OF    CONTENTS. 


INTRODUCTORY   

Multipolar  commutating  dynamos  —  Limits  of  bipolar  dynamos  —  Considerations  governing  choice  of  windings  — 
Cases  in  which  two-circuit  windings  may  be  employed  —  Importance  of  symmetry  —  Extent  to  which  symmetry  may  be 
departed  from  in  certain  cases  —  Gramme  windings  —  Lack  of  symmetry  introduced  by  spider  arms  —  Utility  of  two- 
circuit,  multiple  windings —  Conditions  affecting  voltage  between  adjacent  commutator  segments  —  Slotted  armatures — 
Interdependence  of  re-entrancy,  conductors  per  slot,  number  of  slots,  and  number  of  poles  —  Interpretation  of  formulae  in 
case  of  coils  consisting  of  several  conductors  bound  together  —  Alternate-current  armature  windings. 


PART  I. 
CONTINUOUS-CURRENT  ARMATURE  WINDINGS. 

CHAPTER  I.  —  SINGLE- WOUND  GRAMME  RINGS 

Characteristics  —  Methods  of  cross-connecting  —  Use  of  only  two  sets  of  brushes  with  multipolar  dynamos  —  Methods 
of  reducing  the  number  of  commutator  segments  relatively  to  the  number  of  winding  sections  —  Windings  suitable  for 
poorly  balanced  magnetic  circuits  —  Diminution  of  sparking  by  use  of  resistances. 


CHAPTER  II.  —  DOUBLE- WOUND  GRAMME  RINGS 


Multiple  windings  —  Their  advantages  —  Limiting  conditions  —  Importance  of  symmetry  with  small  numbers  of  con- 
ductors —  Singly  and  multiply  re-entrant  windings  —  Importance  of  avoiding  the  use  of  interpolations  and  cross-connections. 

CHAPTER  III.  —  TWO-CIRCUIT,  SINGLE-WOUND,  MULTIPOLAR  RINGS 

Cases  permitting  the  employment  of  two-circuit  windings  —  Characteristics  —  Lack  of  symmetry  of  the  armature  coils 
—  Short-connection  and  long-connection  types  —  Effect  of  unequal  air  gaps  —  Use  of  long-connection  type  advisable 
for  high  potential  armatures  —  Formulae  and  tables  for  use  with  the  long-connection  gramme  winding — Definition  of 
"  pitch,"  y  —  Table  for  use  in  determining  permissible  angular  distance  between  brushes  with  different  numbers  of 
pOles  —  Examples  of  two-circuit  gramme  windings  —  Chief  objection  to  the  short-connection  type  is  the  great  difference 
of  potential  existing  between  adjacent  sections  of  the  winding  —  Modified  types. 

iii 


iv  TABLE   OF   CONTENTS. 

PAGE 

CHAPTER  IV.  —  TWO-CIRCUIT,  MULTIPLE- WOUND,  MULTIPOLAR  RINGS 40 

Formula  —  Meaning  of  symbols  —  Rule  for  re-en trancy  —  Examples. 

CHAPTER  V.  —  DRUM  ARMATURE  WINDINGS 51 

General  observations  —  Bipolar  drum  windings — The  von  Ilefner-Alteneck  winding  —  Short-chord  windings;  their 
properties  and  limitations  —  Windings  in  which  the  two  active  sides  of  a  coil  are  diametrically  opposite  —  Term  "  conduc- 
tors" often  used  for  convenience,  when  "groups  of  conductors"  would  be  more  exact  —  "One-layer"  and  "two-layer" 
windings  —  Windings  in  which  the  two  short-circuited  coils  are  situated  on  the  same  diameter. 

CHAPTER  VI.  —  MULTIPLE-CIRCUIT,  SINGLE- WOUND,  MULTIPOLAR  DRUMS 71 

Discussion  —  Explanation  of  diagrammatical  methods  for  representing  multipolar  drum  windings  —  Effect  of  different 
pitches  with  same  number  of  face  conductors  —  Connection  at  ends  always  made  between  odd  and  even  numbered  con- 
ductors—  Other  rules  and  limitations  —  Magnitude  of  differences  of  potential  between  adjacent  conductors. 

CHAPTER  VII.  —  MULTIPLE-CIRCUIT,  MULTIPLE-WOUND,  MULTIPOLAR  DRUMS 77 

Rules  controlling  conductors,  pitches,  and  re-entrancy  —  Irregularities  of  windings  much  exaggerated  by  the  small 
number  of  conductors  necessarily  chosen  for  the  illustrative  diagrams  —  Examples  of  various  cases. 

CHAPTER  VIII.  —  TWO-CIRCUIT,  SINGLE- WOUND,  DRUM  ARMATURES 87 

Description  of  characteristics  —  Comparison  of  the  merits  and  faults  of  the  two-circuit  and  multiple-circuit  windings  — 
Formulae  and  rules  for  applying  two-circuit  single  windings  to  drum  armatures  —  Choice  of  even  integers  for  "  y  "  involv- 
ing the  use  of  different  pitches  at  the  two  ends,  but  increasing  the  range  of  choice  —  Comparison  of  the  conditions  with 
one  pair  and  with  several  pairs  of  brushes  upon  the  commutator  —  Description  of  some  two-circuit  windings  with  cross-con- 
nected commutators  possessing  distinctive  features  with  regard  to  the  possible  numbers  of  coils  —  Description  of  a  two-cir- 
cuit drum  winding  devised  by  Wenstrb'm. 

CHAPTER  IX.  —  INTERPOLATED  COMMUTATOR  SEGMENTS 107 

A  study  of  the  distribution  of  potential  in  winding  and  commutator  in  the  case  of  some  two-circuit  drum  windings 
with  interpolated  commutator  segments  —  Discussion  of  results. 

CHAPTER  X.  —  TWO-CIRCUIT,  MULTIPLE- WOUND,  DRUM  ARMATURES 114 

General  formula  —  Meaning  of  symbols  —  Rules  —  Conditions  of  re-entrancy  —  Scheme  of  symbolical  representation 
of  two-circuit  multiple  windings  —  Numerous  examples. 

CHAPTER  XI.  —  THE  SAVERS  WINDING 158 

PART  II. 
WINDINGS  FOR  ALTERNATE-CURRENT  DYNAMOS  AND  MOTORS. 

CHAPTER  XII.  —  ALTERNATING-CURRENT  WINDINGS 163 

Comparison  of  alternating-current  with  continuous-current  windings  —  Special  considerations  involved  in  design  of 
alternating-current  windings  —  Multi-coil  and  uni-coil  windings — Slotted  (or  ironclad)  and  smooth-core  construction  — 
High  and  low  voltage  windings  —  Alternating  continuous-current  commutating  machines  —  Explanation  of  diagrams  — 
Advantages  of  multi-coil  construction  in  certain  cases. 


TABLE   OF   CONTENTS.  v 

PAGE 

CHAPTER  XIII.  —  SINGLE-PHASE  WINDINGS 166 

Examples  of  uni-  and  multi-coil  windings  —  Bar  windings  —  Windings  that  may  be  used  interchangeably  for  single 
and  multiphase  work  —  Advantages  of  symmetry  and  simplicity  —  Windings  that  permit  the  armature  to  be  built  and 
shipped  in  segments  —  Unevenly  distributed  windings. 

CHAPTER  XIV.  —  QUARTER-PHASE  WINDINGS 213 

Meaning  of  the  term  "  uni-coil "  when  applied  to  multiphase  windings —  Examples  of  quarter-phase  windings,  uni-coil 
and  multi-coil  —  Windings  for  quarter-phase,  continuous-current,  commutating  machines  —  Use  of  two-circuit  and  multiple- 
circuit  windings  for  such  machines  —  Ratio  of  collector  ring  to  commutator  voltage  in  this  class  of  commutating  machines. 

CHAPTER  XV.  —  THREE-PHASE  WINDINGS 245 

Typical  diagram  —  Discussion  of  three-phase  windings  —  Rules  regarding  voltage  —  "  Y  "  connection  —  Delta  (A) 
connection  —  Directions  for  making  these  connections — Examples  of  three-phase  windings  —  Induction  motors — Three- 
phase,  continuous-current,  commutating  machines  —  Relation  of  voltage  between  collector  rings  to  continuous-current 
voltage  at  commutator  in  case  of  three-phase,  continuous-current,  commutating  machines. 


PART  III. 

WINDING  FORMULAE  AND  TABLES. 

CHAPTER  XVI.  —  FORMULA  FOR  ELECTROMOTIVE  FORCE 275 

Alternating-current  windings  —  Continuous-current  windings  —  Windings  for  alternating,  continuous-current,  commu- 
tating machines,  quarter-phase  and  three-phase. 

CHAPTER  XVII.  —  METHOD  OF  APPLYING  THE  ARMATURE- WINDING  TABLES  . 277 

Illustrative  examples. 

CHAPTER  XVIII.  —  ARMATURE- WINDING  TABLES 279 

DRUM-WINDING  CONSTANTS 280 

SUMMARIZED  CONDITIONS  FOR  TWO-CIRCUIT  SINGLE  WINDINGS 281 

SUMMARIZED  CONDITIONS  FOR  TWO-CIRCUIT  DOUBLE  WINDINGS 282 

SUMMARIZED  CONDITIONS  FOR  TWO-CIRCUIT  TRIPLE  WINDINGS 283 

WINDING  TABLES  FOR  TWO-CIRCUIT  SINGLE  WINDINGS 285 

WINDING  TABLES  FOR  TWO-CIRCUIT  DOUBLE  WINDINGS 295 

WINDING  TABLES  FOR  TWO-CIRCUIT  TRIPLE  WINDINGS 305 

WINDING  TABLES  FOR  MULTIPLE-CIRCUIT  SINGLE  WINDINGS 315 

WINDING  TABLES  FOR  MULTIPLE-CIRCUIT  DOUBLE  WINDINGS 331 

WINDING  TABLES  FOR  MULTIPLE-CIRCUIT  TRIPLE  WINDINGS 347 


LIST  OF  DIAGRAMS. 


PART   I. 


CHAPTER  I.  — SINGLE- WOUND  GRAMME  RINGS. 


FIGtrRE 

1.  —  Gramme  ring- 

2.  —  Gramme  ring  - 

3.  —  Gramme  ring  - 
1.  —  Gramme  ring  - 

5.  —  Gramme  ring  - 

6.  —  Gramme  ring  - 

7.  —  Gramme  ring  - 

8.  —  Gramme  ring  - 


-  Four-circuit,  single  winding  —  Four  poles 

-  Two-circuit,  single  winding  —  Two  poles 

-  Four-circuit,  single  winding — Four  poles  —  Cross-connected    ........ 

-  Four-circuit,  single  winding  —  Four  poles  —  Cross-connected 

-  Four-circuit,  single  winding  —  Four  poles 

-  Four-circuit,  single  winding  —  Four  poles  —  One-half  normal  number  of  commutator  segments 
-Four-circuit,  single  winding  —  Four  poles  —  One-fourth  normal  number  of  commutator  segments  . 

-  Four-circuit,  single  winding  —  Coils  of  one  circuit  from  brush  to  brush,  not  in  adjacent  fields 


PACE 

3 

3 

5 

6 

9 

10 

13 

14 


CHAPTER   II.  — DOUBLE- WOUND  GRAMME   RINGS. 

9.  —  Gramme  ring  —  Two-circuit,  doubly  re-entrant,  double  winding  —  Two  poles     . 

10.  —  Gramme  ring  —  Four-circuit,  doubly  re-entrant,  double  winding  —  Four  poles  . 

11.  —  Gramme  ring  —  Four-circuit,  singly  re-entrant,  double  winding  —  Four  poles     . 


17 
18 
21 


CHAPTER  III.  — TWO-CIRCUIT,  SINGLE-WOUND,  MULTIPOLAR  RINGS. 


12. —  Gramme  ring  —  Two-circuit,  single 

13.  —  Gramme  ring  —  Two-circuit,  single 

14.  —  Gramme  ring  —  Two-circuit,  single 

15.  —  Gramme  ring  —  Two-circuit,  single 

16.  —  Gramme  ring  —  Two-circuit,  single 

17.  —  Gramme  ring —  Two-circuit,  single 

18.  —  GramTne  ring  —  Two-circuit,  single 

19.  —  Gramme  ring  —  Two-circuit,  single 

imitator  segments  as  coils 


No.  of  poles    No.  of  coils    Pitch      No.  of  commu- 
=  n.                  =  n.            =y.       Utor  segments. 

le  winding  —  Long-connection  type   ...        4               15            7              15 

25 

le  winding  —  Long-connection  type   . 

10 

51 

10 

51 

26 

le  winding  —  Long-connection  type   . 

10 

46 

9 

46 

29 

le  winding  —  Long-connection  type  (modified). 

4 

19 

9 

28 

30 

le  winding  —  Long-connection  type  (modified). 

6 

19 

6 

57 

33 

le  winding  —  Short-connection  type  . 

4 

34 

7&9 

17 

34 

le  winding  —  Short-connection  type  . 

4 

22 

5 

11 

37 

le  winding  —  Long-connection  type  (modified)  — 

-  Four 

poles  —  One-half  as 

many  com- 

38 

Vlll 


LIST  OF  DIAGRAMS. 


CHAPTER  IV.  — TWO-CIRCUIT,  MULTIPLE- WOUND,  MULTIPOLAR  RINGS. 


No.  of  poles    No.  of  coils       No.  of  wind-           Ke- 

=  H.                 =».                 ings  =  ;».          cntranc)-. 

Pitch  =  y. 

-• 

nami 

PAGE 

20.  —  Gramme  ring  —  Two-circuit,  doubly  re-entrant,  double  winding    .4               26                 2             OO 

12 

41 

21.  —  Gramme  ring  —  Two-circuit,  singly  re-entrant,  double  winding              4                24                  2                 © 

11 

42 

22.  —  Gramme  ring  —  Two-circuit,  singly  re-entrant,  double  winding      .6                23                  2                 © 

7 

45 

23.  —  Gramme  ring  —  Two-circuit,  singly  re-entrant,  triple  winding        .4                23                  3                (QQ) 

10 

46 

24.  —  Gramme  ring  —  Two-circuit,  singly  re-entrant,  triple  winding  — 

Twice  normaloiumber  of  commutator  segments        ...        4                23                  3                (QQ) 

10 

49 

CHAPTER  V.  —  DRUM  ARMATURE  WINDINGS. 

25.  —  Bipolar  drum  —  Two-circuit,  single  winding  —  One  layer  —  Sixteen  conductors        

. 

53 

26.  —  Bipolar  drum  —  Two-circuit,  single  winding  —  One  layer  —  Short  chord  —  Thirty-two  conductors  . 

. 

54 

27.  —  Bipolar  drum  —  Two-circuit,  single  winding  —  One  layer  —  Thirty  conductors  —  Two  sides  of  coil  diametrically 

opposite 

57 

28.  —  Bipolar  drum  —  Two-circuit,  single  winding  —  One  layer  —  Short  chord  —  Thirty  conductors 

58 

29.  —  Bipolar  drum  —  Two-circuit,  single  winding  —  One  layer  —  Short  chord  —  Thirty  conductors 

61 

30  (a,  b,  c,  and  </).  —  Bipolar  drums  —  Two-circuit,  single  windings  —  One  and  two  layers  —  Fourteen  and  sixteen  conductors 

62 

31.  —  Bipolar  drum  —  Two-circuit,  single  winding  —  Two  layers  —  Thirty-two  conductors  —  Two  sides  of  coi!  diametrically 

opposite    .................... 

65 

32.  —  Bipolar  drum  —  Two-circuit,  single  winding  —  Two  layers  —  Short  chord  —  Thirty-two  conductors  . 

.        . 

66 

33.  —  Bipolar  drum  —  Two-circuit,  single  winding  —  Two  layers  —  Twenty-eight  conductors  —  Coils  of  outer  and  inner  layers 

69 

CHAPTER  VI.  —  MULTIPLE-CIRCUIT,  SINGLE-  WOUND,  MULTIPOLAR  DRUMS. 

No.  of  poles        No.  of  conductors 
=  «.                          =C 

Pitch  =  ;/. 

34.  —  Multipolar  drum  —  Six-circuit,  single  winding       6                       50 

7  &9 

70 

35.  —  Multipolar  drum  —  Six-circuit,  single  winding       6                       50 

5&7 

73 

36.  —  Multipolar  drum  —  Six-circuit,  single  winding       6                       80 

11&13 

74 

CHAPTER  VII.  —  MULTIPLE-CIRCUIT,  MULTIPLE-  WOUND,  MULTIPOLAR  DRUMS. 

No.  of  poles    No.  of  con-     No.  of  wind-       Re- 

Pitch 

=  ».         ductors=C.      ings  =  771.     entrancy. 

=  !/• 

37.  —  Multipolar  drum  —  Six-circuit,  singly  re-entrant,  triple  winding    .        .        6               50              3             (QQ) 

5&11 

79 

38.  —  Multipolar  drum  —  Four-circuit,  doubly  re-entrant,  quadruple  winding        4               44              4           ©  © 

5&  13 

80 

39.  —  Multipolar  drum  —  Four-circuit,  doubly  re-entrant,  quadruple  winding        4               44              4           ©  © 

7  &  15 

83 

4O.  —  Multipolar  drum  —  Six-circuit,  singly  re-entrant,  double  winding  .        .6               50              2              © 

5&9 

84 

CHAPTER  VIII.  —  TWO-CIRCUIT,  SINGLE-  WOUND,   DRUM  ARMATURES. 

No.  of  poles        No.  ofconduc-        T>I*M 
=  «.                  torB=C. 

41  —  Multipolar  drum  —  Two-circuit,  single  winding  .        .4                     34                    9      

. 

89 

42.  —  Multipolar  drum  —  Two-circuit,  single  winding  ..4                    34              7&9     

. 

90 

43.  —  Multipolar  drum  —  Two-circuit,  single  winding  .        .6                     68                  11      .. 

. 

93 

44  Multipolar  drum  —  Two-circuit,  single  winding  .        .6                     50              7&0     ..... 

. 

94 

LIST   OF   DIAGRAMS. 


ix 


No.  of  poles          No.  of  conduc-            Pitch 

'KURT,                                                                                                                         =n_                   tors  =  C.                =y. 

PAGE 

45.  —  Multipolar  drum  —  Two-circuit,  single  winding  .        .        8                    56                    7         Cross-connected 

commutator      97 

46.  —  Multipolar  drum  —  Two-circuit,  single  winding  .        .8                    48               5&7       Cross-connected  commutator      98 

47.  —  Multipolar  drum  —  Two-circuit,  single  winding  .        .8                    56              7  &  21      Cross-connected 

commutator    101 

48.  —  Multipolar  drum  —  Two-circuit,  single  winding  .        .        8                    52              7  &  19      Cross-connected 

commutator    102 

49.  —  Multipolar  drum  —  Two-circuit,  single  winding  —  Four-pole  wire-wound  armature  (  Wenstrbm) 

.     105 

CHAPTER  IX.  —  INTERPOLATED  COMMUTATOR  SEGMENTS. 

No.  of  poles         p.,  .                 No.  of  conduc- 

No.  of  commu- 

= ».                                            tors=C. 

tator  segments. 

50.  —  Multipolar  drum  —  Two-circuit,  single  winding     6                   13                   80 

80           106 

51.  —  Multipolar  drum  —  Two-circuit,  single  winding     .....        6                     7                   44 

f!li               1O4 

MM9 

4.0  •        n  n 

53.  —  Multipolar  drum  —  Two-circuit,  single  winding     8                     5                   42 

TX^                       J.±\J 

84           113 

CHAPTER  X.  —  TWO-CIRCUIT,  MULTIPLE-  WOUND,  DRUM  ARMATURES. 

No.  of      No.  of        No.  of 

poles    conductors  windings          Ke-entrancy. 

Pitch=y. 

=  «.          =O.           =m. 

54.  —  Multipolar  drum  —  Two-circuit,  singly  re-entrant,  double  winding,      4          32            2                  © 

7         115 

55.  —  Multipolar  drum  —  Two-circuit,  singly  re-entrant,  double  winding,      4          32            2                  © 

7         116 

56.  —  Multipolar  drum  —  Two-circuit,  singly  re-entrant,  triple  winding  .       4           70            3                  (S5) 

15&17    119 

57.  —  Multipolar  drum  —  Two-circuit,  triply  re-entrant,  triple  winding    .4           66            3              OOO 

15          120 

58.  —  Multipolar  drum  —  Two-circuit,  singly  re-entrant,  double  winding,       6           58            2                    (Q) 

9          123 

59.  —  Multipolar  drum  —  Two-circuit,  doubly  re-entrant,  double  winding,      6          52            2                OO 

7  &  9       124 

60.  —  Multipolar  drum  —  Two-circuit,  triply  re-entrant,  triple  winding   .6          60            3             OOO 

9          127 

61.  —  Multipolar  drum  —  Two-circuit,  singly  re-entrant,  triple  winding          6          54            3                 (QQ) 

7  &  9       128 

62.  —  Multipolar  drum  —  Two-circuit,  triply  re-entrant,  triple  winding  .      6          78            3             OOO 

11  &  13     131 

63.  —  Multipolar    drum  —  Two-circuit,    singly     re-entrant,    quadruple 

winding                         .........       6           50            4                 COOO) 

7         132 

64.  —  Multipolar  drum  —  Two-circuit,  quadruply  re-entrant,  quadruple 

winding                                6          56            4          OOOO 

7  &  9      135 

65.  —  Multipolar    drum  —  Two-circuit,    doubly-   re-entrant,    quadruple 

9  &  11     136 

66.  —  Multipolar  drum  —  Two-circuit,  quadruply  re-entrant,  quadruple 

winding               6          80            4          OOOO 

11  &  13    139 

67.  —  Multipolar  drum  —  Two-circuit,  quadruply  re-entrant,  quadruple 

winding                                6        104            4          OOOO 

15  &  17    140 

68.  —  Multipolar  drum  —  Two-circuit,  quadruply  re-entrant,  quadruple 

winding                               6          88            4          OOOO 

15  &  17    143 

69.  —  Multipolar  drum  —  Two-circuit,  triply  re-entrant,  sextuple  winding,      6          66            6             ©  ©  © 

9         144 

70.  —  Multipolar     drum  —  Two-circuit,     doubly     re-entrant,     sextuple 

9  &  11     147 

71.  —  Multipolar  drum  —  Two-circuit,  singly  re-entrant,  sextuple  winding,      6          78            6              Cooooo) 

11          148 

72.  —  Multipolar    drum  —  Two-circuit,    sextuply    re-entrant,    sextuple 

windine-                                                                                                       6           84            6     OOOOOO         11  &  13     151 

X  LIST   OF   DIAGRAMS. 

No.  of  poles     No.  of  con-    No.  of  wind-         Re-  Pitch 

=  n.          ductors=<7.       ing8=?«.       entrancy.                =y.  PAGB 

73.  —  Multipolar  drum  —  Two-circuit,  doubly  re-entrant,  double  winding  .      8                84                2            OO            9&11  152 

74. —  Multipolar  drum  —  Two-circuit,  singly  re-entrant,  double  winding   .8                84                2               (Q)                  11  155 

75.  — Multipolar  drum  — Twc-circuit,  singly  re-entrant,  double  winding    .8                92                2               ©                  11  156 

CHAPTER  XL  — THE  SAYERS  WINDING. 

76.  —  Diagram  of  the  Sayers  winding 159 

PART   II. 
CHAPTER  XII.  — ALTERNATING-CURRENT  WINDINGS. 

CHAPTER  XHI.  — SINGLE-PHASE  WINDINGS. 

77.  —  Uni-coil  winding  —  Two  coils  per  group  —  Sixteen  poles  —  Sixteen  coils 167 

78.  — Uni-coil  winding  — One  coil  per  group  — Twenty-four  poles  — Twelve  coils 168 

79.  —  Bar  winding  —  Twenty-four  poles  —  Twenty-four  conductors 171 

80.  —  Overlapping,  uni-coil  winding  —  Twenty-four  poles  —  Twelve  coils 172 

81.  —  Two-coil  winding  —  One  coil  per  group  —  Sixteen  poles  —  Sixteen  coils 175 

82.  —  Bar  winding  —  Sixteen  poles  —  Thirty-two  conductors 176 

83.  —  Two-coil  winding  —  One  coil  per  group  —  Sixteen  poles  —  Sixteen  coils 179 

84.  —  Overlapping,  two-coil  winding  —  One  coil  per  group  —  Sixteen  poles  — Sixteen  coils 180 

85.  —  Bar  winding  —  Sixteen  poles — Thirty-two  conductors 183 

86. — Overlapping,  two-coil  winding  —  One  coil  per  group  —  Sixteen  poles  —  Sixteen  coils 184 

87.  —  Overlapping,  two-coil  winding  —  Two  coils  per  group  —  Sixteen  poles  —  Thirty-two  coils 187 

88. — Overlapping,  three-coil  winding  —  One  coil  per  group  —  Sixteen  poles  —  Twenty-four  coils       ......  188 

89.  —  Bar  winding  —  Sixteen  poles  —  Forty-eight  conductors 191 

90.  — Overlapping,  three-coil  winding  — One  coil  per  group— Sixteen  poles— Twenty-four  coils 192 

91.  —  Bar  winding  —  Sixteen  poles  —  Forty-eight  conductors 195 

92.  —  Partially  overlapping,  three-coil  winding  —  One  coil  per  group  —  Sixteen  poles  —  Twenty-four  coils        ....  196 

93.  —  Bar  winding  —  Sixteen  poles  —  Forty-eight  conductors 199 

94.  —  Partially  overlapping,  three-coil  winding  —  One  coil  per  group  —  Sixteen  poles  —  Twenty-four  coils        ....  200 

95.  —  Three-coil  winding  —  One  coil  per  group  —  Sixteen  poles  —  Twenty-four  coils 203 

96-  —  Non-overlapping  winding  with  one  and  one-half  coils  per  pole  piece  —  Two  coils  per  group  —  Twenty  poles  —  Thirty  coils  .  204 

97.  —  Unevenly  distributed,  two-coil  winding  —  Twelve  poles  —  Twelve  coils 207 

98.  —  Unevenly  distributed  bar  winding  —  Eight  poles  —  Twenty-four  conductors 208 

99.  —  Unevenly  distributed  two-coil  winding  —  Sixteen  poles  —  Sixteen  coils 211 

CHAPTER  XIV.  —  QUARTER-PHASE  WINDINGS. 

100.  —  Overlapping,  uni-coil  winding  —  One  coil  per  group  —  Sixteen  poles  —  Sixteen  coils 212 

101.  —  Bar  winding  —  Sixteen  poles  —  Thirty-two  conductors 215 

102.  —  Non-overlapping,  uni-coil  winding  —  Two  coils  per  group  —  Eight  poles  —  Sixteen  coils 216 

103.  — Overlapping,  uni-coil  winding  — Two  coils  per  group  — Sixteen  poles  — Thirty-two  coils 219 

104.  —  Two-coil  winding  —  Twelve  poles  —  Twenty-four  coils 220 


LIST   OF   DIAGRAMS.  xi 


PAGE 


105.  —  Two-coil  winding  —  Twelve  poles  —  Twenty-four  coils 223 

106.  —  Bar  winding  —  Twelve  poles  —  Forty-eight  conductors 224 

107.  —  Bar  winding  —  Twelve  poles  —  Forty-eight  conductors 227 

108.  —  Bar  winding  —  Twelve  poles  —  Forty-eight  conductors 228 

109.  —  Bar  winding  —  Twelve  poles  —  Forty-eight  conductors 231 

110.  —  Three-coil  winding  —  Eight  poles  —  Twenty-four  coils 232 

111.  —  Three-coil  winding  —  Eight  poles  —  Twenty-four  coils 235 

112.  —  Bar  winding  —  Eight  poles  —  Forty-eight  conductors 236 

113.  —  Bar  winding  —  Eight  poles  —  Sixty-four  conductors     ..............  239 

114.  —  Two-circuit  winding  for  quarter-phase,  continuous-current,  commutating  machine  —  Six  poles  —  Sixty-eight  conductors  240 

115.  —  Twelve-circuit  winding  for  quarter-phase,  continuous-current,  commutating  machine  —  Twelve  poles — 144  conductors    .  243 

CHAPTER  XV.  —  THREE-PHASE   WINDINGS. 

116.  —  Uni-coil  winding — Twenty  poles  —  Thirty  coils 244 

117.  —  Diagrams  showing  "  delta  "  (A)  and  "  Y  "  connections         .............  247 

118.  —  Bar  winding  —  Twenty  poles  —  Sixty  conductors 248 

119.  —  Non-overlapping  winding  —  Two  coils  per  group  —  Twenty  poles  —  Thirty  coils  —  One  and  one-half  coils  per  pole  piece 

per   phase 251 

120.  —  Bar  winding  —  Twenty  poles — Sixty  conductors 252 

121.  —  Two-coil  winding  —  Eight  poles  —  Twenty-four  coils 255 

122.  —  Bar  winding  —  Eight  poles  —  Forty-eight  conductors 256 

123.  —  Two-coil  winding  —  Eight  poles  —  Twenty-four  coils 259 

124.  —  Bar  winding  —  Eight  poles  —  Forty-eight  conductors 260 

125.  —  Bar  winding  —  Six  poles  —  Fifty-four  conductors 263 

126.  —  Bar  winding — Four  poles  —  Fifty-one  conductors 264 

127.  —  Bar  winding  —  Six  poles — Fifty-one  conductors 267 

128.  —  Two-circuit  winding  for  a  three-phase,  continuous-current,  commutating  machine  —  Six  poles  —  Sixty-eight  conductors  268 

129.  —  Six-circuit  winding  for  a  three-phase,  continuous-current,  commutating  machine  —  Six  poles  — 108  conductors     .        ,  271 


INTRODUCTORY. 


THE  present  treatise  is  the  outcome  of  an  investigation  made  a  number  of  years  ago,  before  the  principles 
of  the  armature  winding  of  multipolar  commutating  dynamos  were  generally  understood  by  electricians.  At 
that  time  it  appeared  that  the  demand  for  dynamos  of  greater  current  output  could  only  be  met  satisfactorily 
by  dynamos  of  the  multipolar  type,  since  with  bipolars  beyond  a  certain  output  the  number  of  commutator 
segments  compatible  with  freedom  from  sparking  was  found  to  be  incompatible  with  the  maximum  armature 
reaction  which  experience  has  shown  to  be  permissible.  After  some  study  it  was  concluded  the  only  feature  of 
the  multipolar  dynamo  requiring  special  study  was  that  of  the  armature  windings. 

A  considerable  number  of  diagrams  were  prepared  and  classified ;  the  advantages  and  disadvantages  of 
each,  and  the  comparative  fitness  of  these  windings  for  different  purposes,  noted.  Inasmuch  as  it  was  found 
convenient  to  refer  to  this  data  frequently,  and  on  account  of  the  comparative  inaccessibility  of  such 
information  when  in  the  form  of  notes,  we  decided  that  it  would  be  a  great  convenience  to  electricians 
generally  if  our  notes  were  published  in  book  form.  We  therefore  proceeded  to  do  this ;  but  owing  to  the 
intervention  of  certain  circumstances  contingent  to  our  position  in  an  industrial  concern,  it  became  necessary 
to  lay  aside  this  work  until  those  competent  to  judge  of  its  nature  should  feel  able  to  permit  us  to  proceed  as  we 
had  wished.  The  delay  has  not  been  disadvantageous,  since  in  the  meantime  we  have  not  laid  the  work  aside ; 
on  the  contrary,  we  have  made  a  study  of  the  properties  of  a  number  of  the  more  important  windings,  so  that 
the  original  manuscript  has  been  largely  added  to. 

In  the  section  on  continuous-current  armature  windings  our  endeavor  has  been  to  include  only  those 
windings  that  possess  some  practical  merit,  and  we  have  frequently  pointed  out  the  advantages  and  disad- 
vantages peculiar  to  certain  classes  of  windings.  The  thought  will  probably  occur  to  the  reader,  which  one  of 
these  windings  should  be  selected  for  a  given  .voltage  after  the  number  of  poles  and  the  magnitude  of  the 
magnetic  flux  at  the  poles  have  been  assigned  a  proper  value.  We  cannot  point  out  the  fitness  of  each  winding 
for  a  given  purpose,  since  this  is  more  or  less  dependent  upon  the  magnetic  characteristics  peculiar  to  any 
particular  design.  Thus  in  some  machines  of  particularly  good  characteristics  two-circuit  windings  have  been 
used  in  the  generation  of  comparatively  large  currents  with  some  success,  when  had  the  magnetic  charac- 
teristics of  the  dynamos  been  ordinarily  good,  the  use  of  the  two-circuit  winding  would  have  been  attended 
with  results  entirely  unsatisfactory. 

xiii 


xiv  INTRODUCTORY. 

In  general,  we  may  state,  the  type  of  winding  should  be  determined  with  reference  to  the  magnitude  of  the 
current  to  be  generated.  Any  deviation  from  a  perfectly  symmetrical  arrangement  of  the  armature  conductors 
should  be  inversely  proportional  to  the  magnitude  of  the  currents  to  be  generated.  When  the  currents  to  be 
generated  are  large,  the  coils  should  be  similarly  situated  with  respect  to  each  other,  and  should  all  have  the 
same  resistance  and  inductance.  It  has  been  frequently  found  that  when  the  conductors  are  dissimilarly 
situated  with  respect  to  each  other  or  to  any  other  body  that  can  affect  the  armature  conductors  inductively, 
the  wearing  away  of  the  commutator  is  uneven,  the  trouble  increasing  more  and  more  as  the  currents  in  the 
conductors  are  increased,  or  the  resistance  of  the  collecting  brushes  diminished.  Especially  in  armatures  in 
which  there  are  more  than  two  coils  in  a  slot  this  uneven  wearing  away  of  the  commutator  has  been  noticed. 
In  this  case  the  coils  are  of  slightly  unequal  area,  due  to  the  progression  of  the  winding  from  slot  to  slot. 

In  gramme  windings  the  lack  of  symmetry  may  be  due  to  some  of  the  coils  being  longer  than  the  others, 
or  carried  near  the  spider  arms. 

It  may,  therefore,  be  stated  generally  that  when  a  given  result  has  to  be  obtained  without  experimenting, 
such  windings  as  these  are  to  be  avoided  when  the  currents  in  the  conductors  have  to  be  of  any  considerable 
magnitude. 

The  utility  of  the  double,  triple,  and  quadruple  windings  shown  and  described  depends  very  largely  upon 
the  maximum  arc  upon  the  commutator  over  which  uniform  contact  resistance  can  be  obtained.  With  the 
thickness  of  segments  now  common  in  practice,  only  double  and  triple  windings  appear  to  be  of  practical  value, 
since,  in  general,  brushes  cannot  be  relied  upon  to  maintain  a  uniform  contact  over  an  arc  of  much  more  than 
three-quarters  of  an  inch  in  width.  When  the  width  of  the  brush  has  to  exceed  this  amount,  it  is  found  that  it 
bridges  imperfectly  from  commutator  bar  to  commutator  bar  in  the  same  winding,  thereby  causing  sparking. 

A  feature  peculiar  to  these  windings,  as  well  as  to  some  of  the  two-circuit  single  windings,  is  that  the 
voltage  between  adjacent  commutator  sections  is  affected  by  the  angular  distance  between  the  different  sets  of 
collecting  brushes.  With  some  of  these  windings  the  voltage  between  adjacent  commutator  sections  varies 
simply  according  to  the  field  strength  when  the  angle  between  the  different  sets  of  brushes  corresponds  to  the 
angle  between  the  centers  of  the  poles.  In  other  windings  the  voltage  between  adjacent  commutator  sections 
varies  by  jumps,  but  may  be  made  to  vary  according  to  the  field  strength  by  slightly  varying  the  position  of 
some  one  set  of  brushes  with  respect  to  the  other  sets.  This  feature  of  the  different  windings  is  a  subject  for 
special  investigation,  and  is  of  more  or  less  importance,  according  to  the  nature  of  the  winding  and  the  average 
voltage  between  commutator  bars. 

We  have  frequently  made  mention  of  the  number  of  slots.  With  respect  to  slotted  armatures  in  general, 
it  is  to  be  remembered  that  an  additional  condition  to  that  for  smooth-core  armatures  has  to  be  fulfilled ;  i.e.  the 
total  number  of  the  conductors  to  suit  the  equations  for  re-entrancy  has  to  be  divisible  by  the  number  of 
conductors  possible  to  place  in  a  slot,  this  number  being  dependent  upon  the  number  of  poles.  The  number  of 
conductors  permissible  per  slot  for  two-circuit  windings  for  different  numbers  of  poles  is  shown  in  a  table. 

We  have  omitted  any  reference  to  mechanical  details  of  construction  of  armature  windings,  since  these 
permit  of  great  variety,  without  in  any  way  modifying  the  results.  Further,  they  are  a  part  of  the  stock  in 
trade  of  the  electrical  manufacturer. 

The  drum  windings  considered  are  principally  those  in  which  the  end  connections  are  interchangeable,  and 


INTKODUCTOEY.  xv 

are  in  the  form  of  evolutes,  as  in  the  Eickemeyer  and  Hopkinson  windings,  description  of  which  will  be  found 
in  Weymouth's  "Drum  Armatures  and  Commutators"  ("The  Electrician"  Printing  and  Publishing  Company, 
London,  1893).  In  general,  such  windings  possess  the  advantages  that  all  coils  are  of  equal  inductance  and 
resistance,  are  equally  accessible,  have  equal  radiating  surfaces,  and  are  most  easily  repaired.  When  a  coil 
consists  of  a  number  of  conductors,  bound  together  so  as  to  be  considered  a  single  unit  mechanically,  it  is  so 
considered  in  the  text,  and  in  the  formulae  for  the  arrangement  of  conductors. 

These  windings  appear  to  have  been  invented  by  Bollmann,  Desroziers,  Fritsche,  Pischon,  Eickemeyer, 
and  others ;  but  inasmuch  as  it  is  a  disputed  question  as  to  which  of  these  inventors  has  the  right  to  claim 
priority,  and  as  there  may  be  more  or  less  litigation  before  the  question  is  settled,  we  have  considered  it  best  to 
omit  all  discussion  as  to  who  may  have  invented  any  of  the  windings.  Where  with  a  winding  is  given  the 
name  of  a  supposed  inventor,  it  is  simply  because  that  winding  has  been  known  under  that  name,  and  not 
because  the  writers  possess  any  special  evidence  to  show  by  whom  the  winding  was  invented.  After  the 
possibility  of  litigation  has  ceased  we  hope  to  do  justice  to  all  inventors  concerned,  giving  to  each  his  proper 
proportion  of  credit  for  the  work  he  has  done. 

We  believe  that  the  tables  on  drum  windings  are  a  feature  that  should  meet  with  especial  favor,  since 
after  the  number  of  conductors  required  for  a  given  type  of  winding  has  been  determined,  the  proper  pitches 
for  any  style  of  winding  can  be  found  in  the  tables.  Further,  by  referring  opposite  to  this  number  of  con- 
ductors in  the  different  tables  it  may  be  ascertained  at  a  glance  whether,  by  slightly  changing  the  end 
connections,  the  winding  may  be  adapted  to  some  other  voltage.  Such  features,  peculiar  to  certain  numbers  of 
conductors,  are  frequently  in  practice  of  the  greatest  importance.  As  a  practical  example  take  the  following 
case  :  In  a  six-pole  machine  with  104  armature  conductors,  the  winding  may  be  connected  for  a  two-circuit 
single  winding  by  making  the  pitch  17  on  each  end,  or  for  a  two-circuit,  doubly  re-entrant  double  winding,  by 
making  the  pitch  17  on  one  end  and  19  on  the  other;  this  second  arrangement  being  suitable  for  the  same  watt 
output  as  the  first,  at  one-half  the  voltage. 

In  the  section  on  alternate-current  armature  windings  are  included  a  number  of  windings  that  have  now 
only  a  limited  application  in  practice,  as  it  is  thought  that,  on  account  of  the  very  limited  literature  on  this 
subject,  a  description  of  all  windings  of  any  practical  use  will  be  appreciated. 

With  respect  to  the  work  in  general,  we  should  be  glad  to  receive  the  suggestions  and  criticisms  of  all  who 
are  interested  in  this  subject. 

The  following  articles  on  armature  windings  have  been  consulted  in  the  preparation  of  this  book,  and  are 
mentioned  here  for  reference :  — 

ARNOLD —  Die  Ankerwicklungen  der  Gleichstrom-Dynamomasohinen.     Berlin,  1891. 

FRITSCHE  —  Die  Gleichstrom-Dynamomaschine.     Berlin,  1889. 

KAPP — Practical  Electrical  Engineering,  Vol.  II.,  p.  43.     London,  1893. 

KITTLER  —  Handbuch  der  Elektrotechnik,  Vol.  I.     Stuttgart,  1892. 

RECHNIEWSKI  —  L'Electricien,  Vol.  V.    Jan.  14,  1893  el  seq. 

THOMPSON  —  Dynamo-Electric  Machinery.     London,  1892. 

WEYMOUTH  —  The  Electrician,  Vol.  *X¥".     Nov.  7  to  Dec.  19,  1890. 


PAET  I. 

CONTINUOUS-CURRENT  ARMATURE  WINDINGS. 


CHAPTER  I. 

SINGLE-WOUND  GRAMME  RINGS. 

THESE  are  the  simplest  windings  in  use,  and  will  require  only  a  very  few  diagrams  and  explanations.  Many 
complex  connections  have  been  proposed,  but  only  such  forms  will  be  discussed  as  are  of  general  practical  use. 

The  plain  gramme  ring,  with  a  single  winding,  is  shown  in  Figs.  1  and  2,  from  which  it  may  be  seen  that 
the  construction,  as  far  as  concerns  location  of  coils,  connectors,  and  commutator  segments,  is  independent  of 
the  number  of  poles.  The  number  of  coils  should  be  a  multiple  of  the  number  of  poles  in  order  to  maintain 

s 


Fig.  I 
FOUR-CIRCUIT,  SINGLE-WINDING, 


Fig.  2 
TWO-CIRCUIT,  SINGLE-WINDING, 


symmetry  among  all  the  branches  from  brush  to  brush.     The  number  of  commutator  segments  is  equal  to  the 
number  of  coils.     It  is  desirable  to  minimize  the  turns  per  coil,  and  consequently  the  inductance  of  the  short- 1 
,'circuited  elements,  by  as  large  a  number  of  segments  as  practicable. 

A  further  discussion  of  these  two  diagrams  would  be  superfluous,  beyond  calling  attention  to  the  progressive 
nature  of  the  rise  of  potential  around  the  ring,  whereby  the  contiguous  wires  have  only  the  small  difference 
of  potential  of  one  turn,  making  the  question  of  insulation  very  simple. 

8 


ARMATURE  WINDINGS  OF  ELECTRIC   MACHINES.  [OHAP. 


In  cases  where  it  is  desirable  to  use  but  two  brushes  in 
multipolar  rings  with  more  than  two  circuits,  the  method  of 
cross-connecting,  shown  in  Fig.  3,  may  be  used.  The  num- 
ber of  commutator  segments  remains  equal  to  the  number  of 
coils.  An  inspection  of  the  diagram  will  show  that  it  really 
consists  in  connecting  in  parallel  those  coils  occupying  cor- 
responding positions  in  the  various  fields. 

It  would  seldom  be  desirable  to  utilize  this  method  of 
connection,  except  in  very  small  machines,  as  the  use  of  only 
one  pair  of  sets  of  brushes  would  necessitate  lengthening  the 
commutator  in  order  to  retain  the  proper  extent  of  brush 
contact  surfaces. 


^45*^ 

or  ma 

USI7BRSITY] 


Fig.  3 
FOUR  CIRCUIT,  SINGLE  WINDING. 


Fig.  4 
FOUR  CIRCUIT  SINGLE  WINDING 


CHAP,  i.]  SINGLE-WOUND   GKAMME  KINGS. 


Figure  4  differs  from  Fig.  3  only  in  the  use  of  two  cross- 
connecting  leads  instead  of  one.  This  diagram  would  some- 
times be  of  advantage,  inasmuch  as  it  utilizes  the  available 
space  more  completely  and  symmetrically.  Each  cross- 
connecting  conductor  could  be  of  smaller  cross-section  than 
if  only  one  were  used. 

Both  this  and  the  preceding  method  have  the  disadvantage 
that  the  two  parallel  sections  have  unequal  resistance,  due  to 
one  section  having  the  long  cross-connecting  leads  in  series 
with  it,  and  the  other  merely  the  regular  short  leads  to  the 
commutator. 

Failure  to  give  due  attention  to  this  point  often  causes 
serious  trouble. 


AKMATUBE  WINDINGS  OF  ELECTKIC  MACHINES.  [CHAP.  i. 


Figure  5  gives  a  winding  which  is  wrong,  but  which  has 
been  given  in  the  treatises  of  many  of  the  specialists  on 
windings,  none  of  whom,  except  Herr  Arnold,  criticise  it. 

The  fault  is  that  the  positions  of  the  coils  bear  such  a 
relation  to  the  positions  of  their  respective  commutator  seg- 
ments, that  during  each  revolution  of  the  armature  the 
position  given  in  the  figure  is  the  only  one  in  which  the 
brushes  are  properly  placed  with  regard  to  the  diameter  of 
commutation.  In  order  that  the  brushes  should  always  be  in 
a  position  to  properly  perform  their  commutative  function, 
they  would  have  to  be  revolved  in  a  direction  opposite  to 
that  of  the  armature,  and  with  a  velocity  equal  to  it. 

The  characteristic  of  the  winding  is  that  it  brings  together 
into  one  segment  each  pair  of  cross-connected  segments  of 
the  previous  diagram.  As  above  stated,  however,  this  dia- 
gram is  worthless,  except  to  call  attention  to  its  character,  so 
that  the  text-books  in  which  it  is  described  shall  not  be  mis- 
leading. 

See    ARNOLD  —  Die     Ankerwicklungen     der     Gleichstrom-Dynamoma- 

schinen,  Fig.  42. 

KITTLER  — Handbuch  der  Elektrotechnik,  1892,  Fig.  401  C. 
FRITSCHE  —  Die  Gleichstrom-Dynamomaschiuen,  Fig  64. 


W//A 

Fig.  5 
FOUR  CIRCUIT  SINGLE  WINDING. 


Fig.  6 
FOUR  CIRCUIT  SINGLE  WINDING. 


CHAP,  i.]  SINGLE-WOUND   GRAMME    KINGS.  11 


In  Fig.  6  the  number  of  commutator  segments  is  made 
equal  to  half  the  number  of  coils  by  connecting  two  coils  in 
series  between  each  pair  of  adjacent  segments.  The  coils  so 
connected  in  series  are  situated  in  adjoining  fields  of  opposite 
polarity.  This  winding  has  the  disadvantage  that  coils  at 
quite  different  potentials  are  adjacent,  as  may  be  seen  by  fol- 
lowing through  the  various  armature  circuits  from  brush  to 
brush.  This  increases  the  difficulty  of  insulating.  The  volts 
per  bar  also,  for  the  same  number  of  conductors  per  coil,  are 
twice  as  high  as  in  the  simple  gramme  ring.  If  it  is  necessary, 
for  any  reason,  to  halve  the  number  of  bars,  it  would  be  pref- 
erable to  combine  two  adjacent  coils  into  one,  and  retain  the 
advantages  of  the  simple  gramme  ring  connection. 

But  in  cases  where  the  shape  of  the  frame  necessitates 
somewhat  unequal  magnetic  circuits,  this  connection  averages 
up  the  unequal  induction  in  the  various  coils,  and  therefore 
tends  to  diminish  the  sparking  which  might,  with  a  simple 
gramme  ring  in  such  an  unbalanced  magnetic  system,  be 
considerable. 

If  *  =  number  of  coils,  and  n  =  number  of  poles,  then  any 

coil  is  connected  across  to  one  (  -  ±  1 )  in  advance  of  it,  and 

\>i      J 

the  two  free  ends  of  this  pair  of  coils  are   connected   to 
adjacent  commutator  segments. 


12  AEMATUKE  WINDINGS  OF  ELECTRIC   MACHINES.  [CHAP. 


Figure  7  is  merely  a  step  in  advance  of  Fig.  6,  and  the 
advantages  and  disadvantages  pointed  out  in  the  discussion 
of  Fig.  6  apply  in  still  greater  degree  to  Fig.  7. 

It  will  be  seen  that  the  number  of  commutator  segments 
is  reduced  to  one-fourth  of  the  number  of  coils  by  the  con- 
necting in  series  of  four  coils,  one  in  each  field,  between  two 
adjacent  segments  of  the  commutator. 

As  in  the  previous  figure,  the  rule   for  connecting  the 

coils  is  to  connect  each  coil  to  one  (  -  ±  1 )  in  advance. 

\n       J 


Fig.  7 
FOUR  CIRCUIT  SINGLE  WINDING. 


WMWM. 

Fig.  8 
FOUR  CIRCUIT,  SINGLE  WINDING, 


CHAP,  i.]  SINGLE-WOUND   GRAMME   EINGS.  15 


Figure  8  represents  a  winding  in  which  the  coils  of  one  circuit,  from 
brush  to  brush,  instead  of  being  adjacent  to  each  other,  are  situated  in 
different  fields.  For  instance,  the  circuits  through  the  armature  in  the 
position  shown  are,  — 


8      1      6 

j  2      7     121 
1  9      4     11  I 

It  is  important  to  note  that  when  the  armature  has  entered  the  posi- 
tion in  which  four  coils  are  short-circuited,  the  short-circuiting  of  any  coil 
occurs,  not  at  any  one  brush,  but  through  the  pair  of  brushes  of  like  polarity. 
This  would  enable  sparking  to  be  diminished  by  connecting  the  two  positive 
brushes  together  through  a  suitable  resistance  (ohmic  or  inductive),  and  lead- 
ing off  to  the  load  from  the  middle  point  of  this  resistance.  The  magnitude 
of  the  resistance,  if  ohmic,  would  be  limited  only  by  the  permissible  loss 
therein.  High  resistance  leads  to  the  commutator,  and  high-resistance 
brushes  have  been  used  with  considerable  success  ;  but  in  both  of  these 
cases  heat  has  to  be  developed  in  undesirable  localities.  But  in  the  above 
method  of  connection,  the  insertion  of  this  resistance  externally  to  the 
brushes  will  not  increase  the  heating  of  the  machine.  This  resistance  is  also 
so  located  that  it  could  be  adjusted  in  experimental  work,  and  the  differ- 
ence in  sparking  noted  by  having  a  short-circuiting  switch  shunted  around 
the  resistance. 

Another  advantage  of  this  winding  is  that  pointed  out  in  the  remarks  on 
Fig.  6,  that  in  cases  where  the  shape  of  the  frame  necessitates  somewhat 
unequal  magnetic  circuits,  this  connection  will  average  up  the  unequal 
induction  in  the  various  coils,  and  thereby  diminish  the  sparking  that 
would  otherwise  occur. 


CHAPTER  II. 

DOUBLE- WOUND  GRAMME  RINGS. 

FIGURE  9  and  the  immediately  following  diagrams  relate  to  a  class  of  very  great  importance,  which 
are  known  as  double,  triple,  quadruple,  etc.,  windings. 

Very  satisfactory  results  have  been  attained  by  the  use  of  windings  of  this  class.  The  most  important 
advantage  of  the  double  winding  is  that  the  current  is  commutated  at  two  different  parts  of  the  bearing 
surface  of  the  brush ;  each  independent  volume  of  current  being,  therefore,  only  one-half  of  what  it  would 
be  for  a  single  winding.  The  importance  of  this  feature  has  in  practice  been  found  to  be  very  great. 

Another  important  feature  of  this  winding  is  that  the  successive  commutator  bars  of  one  winding  are 
not  adjacent  to  each  other,  but  alternate  with  the  bars  of  the  other  winding ;  the  two  windings  being  put 
in  parallel  by  the  use  of  wide  brushes.  The  result  is  that  a  section  is  very  unlikely  to  be  short-circuited 
by  dirt  or  an  arc.  It  also  makes  a  very  flexible  winding,  owing  to  the  readiness  with  which  any  number 
of  parallels  may  be  arranged.  Thus,  in  a  six-pole  field,  we  may  have  four,  six,  eight,  etc.,  parallels. 

It  is  necessary  for  a  double  winding  that  the  brush  should  bear  over  a  surface  greater  than  the  width 
of  one  segment  (plus  insulation);  for  a  triple  winding,  greater  than  the  width  of  two  segments,  etc. 

In  Fig.  9,  which  represents  a  two-circuit,  doubly  re-entrant,  double-wound,  simple  gramme  ring,  the 
circuits  through  the  armature  are,  — 

9       10         1         2         31 
8         7         6         5         4  J 

'      10'        1'         2'        3'  1 

7'        6'         5'        4'J 

After  the  armature  has  revolved  through  -      -^=9°,   coils   3  and    8  will    be  short-circuited,   and    the 


circuits  through  the  armature  will  become,— 


|9 

10 

1 

2 

—  -i 

17 

0 

5 

4 

-i9' 
18' 

10' 

7' 

1' 
6' 

2' 
5' 

4'P 

Thus  it  will  be  seen  that  there  will  be  a  lack  of  balance  between  the  two  windings.  First  they  will 
be  of  equal  length ;  after  9°  revolution,  one  will  have  one  less  section  in  series  between  the  brushes ; 
9°  later  they  will  be  equal  again ;  and  after  still  another  9°  the  other  winding  will  have  the  smaller 
number  of  turns.  This  lack  of  symmetry  will  be  less  apparent  as  the  number  of  sections  is  increased, 
and  becomes  of  very  little  importance  with  the  large  numbers  of  conductors  employed  in  practical  work. 

10 


Fig.  9 
TWO  CIRCUIT  DOUBLE  WINDING 


Of  THS  ^ 

I7BRSJ 


Fig.  10 
FOUR  CIRCUIT  DOUBLE  WINDING. 


VlIIAl'.  II.] 


DOUBLE-WOUND   GRAMME   RINGS. 


19 


Figure  10  shows  a  similar  winding  in  a  four-pole  field. 
The  circuit  through  the  armature  in  the  position  shown  is,  — 


|  16         17 

18 

19 

20  \ 

~  1  15         14 

13 

12 

H\>  + 

f  16'        17' 
(  15'        14' 

18' 
13' 

19' 

12' 

20'/^>  + 
11  '^ 

|    6           7 

8 

9 

10  x 

15           4 

3 

2 

lsO>.+ 

!    6'          7' 

8' 

9' 

10"^>  + 

15'          4' 

3' 

2' 

v<^ 

After  turning  through 

360 

4  ^ 

",  coils  15',  20',  5',  and 

40  x 

2 

10'  will  be  short-circuited 

,  and 

the  circuits  through  the  arma- 

ture  will  be,  — 

f  16         17 

18 

19 

20-v 

"  1  15         14 

13 

12 

1Kv>  + 

r  16'       17' 
"  1  14'        13' 

18' 
12' 

19' 
11' 

I/>  + 

f    6           7 
"  1    5           4 

8 
3 

9 

2 

i;\>+ 

f    6'          7' 

8' 

9' 

—  ^S+ 

1    4'          3' 

2' 

1' 

—  ^ 

Here  can  be  seen  again  the  lack  of  symmetry  noted  in  re- 
marks on  Fig.  9. 


20 


ARMATURE   WINDINGS   OF   ELECTRIC   MACHINES. 


[cllAl1.    II. 


A  very  useful  winding  is  that  shown  in  Fig.  11.  It,  also,  is  a  four-circuit  double  winding.  It  is  one 
of  a  class  with  very  interesting  properties.  It  differs  from  the  double  winding  shown  in  Fig.  10,  in  that 
the  two  windings  are  components  of  one  re-entrant  system.  Any  one  section  is  no  longer  exclusively  an 
element  of  one  of  two  windings,  but  changes  from  one  winding. to  the  other  four  times  per  revolution, 
being  short-circuited  at  the  neutral  point  for  a  brief  period  at  the  occurrence  of  eacli  of  these  transfers. 
These  features  are  secured  by  adding  one  section  to  the  doubly  re-entrant  double  winding  shown  in  Fig. 
10,  and,  as  in  that  figure,  making  the  connections,  not  between  adjacent  sections,  but  always  by  passing 
over  one  section.  The  number  of  sections  being  odd,  it  will  be  seen  that  after  having  progressed  twice 
around  the  ring,  all  sections  will  have  been  passed  through,  and  the  winding  will  have  arrived  at  the 
other  terminal  of  the  section  from  which  it  started. 

Triple,  quadruple,  and  higher  orders  of  windings  may  be  treated  analogously.1 

The  circuits  through  the  armature  in  the  position  shown  in  Fig.  11  are, — 


f-i11 

1    9 

12 
8 

J21 

1 

"  I  20 

19 

r    5 

6 

"  (    4 

3 

f  16 

17 

-lie 

14 

Coil  10  is,  at  this  instant,  short-circuited.     An  instant  later  coil  10  becomes  active,  and  coil  2  becomes 
short-circuited.     The  circuits  through  the  armature  then  become,  — 


-I10 
1    9 

11 

8 

[21 

1 

"  I  20 

19 

1    5 

6 

4 

3 

rie 

17 

1  15 

14 

1 


The  order  in  which   the   various  coils  will   be  short-circuited   is  10,   2,  15,  7,   20,   12,  4,    17,  etc.,  no 
that  the  21  coils  will  each   have  been  short-circuited  once  when  the  armature  shall  have   revolved  through 

360° 

——  =  90°.      Therefore    the    angular    interval    between    corresponding    positions    of    two    successive    short 

90o 
circuits  is   ~o~^'^°' 


1   Such  windings  will  be  designated  as  singly  re-entrant,  to  distinguish   them   from   others,  such   as  those  of   Figs.  9  and 
10,  which  are  doubly  re-entrant. 


Fig.  1  1 
FOUR  CIRCUIT  DOUBLE  WINDING 


UHI7BR3ITY 


22  ARMATURE   WINDINGS   OF   ELECTRIC   MACHINES  [CHAP.  n. 


All  of  the  windings  so  far  described  have  as  many  cir- 
cuits through  the  armature  as  there  are  pole  pieces,  and 
form  a  class  by  themselves  known  as  multiple-circuit  wind- 
ings. Four-pole  fields  have  usually  been  considered,  but 
the  modifications  of  the  diagrams  and  text  to  apply  them 
to  larger  numbers  of  poles,  are  obvious. 

In  general,  the  number  of  sets  of  brushes  equals  the 
number  of  poles  and  the  number  of  circuits  through  the 
armature.  Different  numbers  of  segments  and  brushes  are 
due  to  modifications,  and  do  not  affect  the  underlying 
character  of  the  windings  as  a  class.  Some  of  these 
modifications  have  been  described.  Others  can  be  worked 
out  as  the  occasion  requires. 

Too  much  importance  cannot  be  attached  to  the  general 
rule  that  interpolations  and  cross-connections  are  almost 
always  very  undesirable. 


CHAPTER   III. 

TWO-CIRCUIT,   SINGLE-WOUND,  MULTIPOLAR  RINGS. 

THE  next  windings  to  be  considered  form  a  class  which,  independently  of  the  number  of  poles,  have 

only  two  circuits  through  the  armature.     These  are  known  as  two-circuit  windings.     Such  windings  possess 

2 
the  practical  advantage  that  the  number  of  conductors,  as  compared  with  multiple-circuit  windings,  is  only  — 

2 
as  great,  hence  the  space  required  for  insulation  is  only  -^-  as  great  as  with  the  multiple-circuit  windings,  in 

consequence  of  which  the  diameter  of  the  armature,  or  the  depth  of  space  occupied  by  the  armature 
conductors,  may  be  less  than  with  the  multiple -circuit  windings,  thereby  diminishing  the  cost  of  material. 

Further,  on  account  of  the  lesser  number  of  conductors,  the  cost  of  the  labor  of  winding  is  corre- 
spondingly diminished. 

In  practice,  the  two-circuit  gramme  windings  have  been  applied  only  to  armatures  of  small  output, 
under  which  condition  lack  of  symmetry  of  the  armature  coils  with  respect  to  the  points  of  commutation 
is  not  particularly  objectionable.  Only  two  sets  of  collecting  brushes  are  necessary  for  the  collection  of 
current ;  in  practice  generally  but  two  sets  have  been  used. 

In  the  "  short-connection " l  type  of  two-circuit  gramme  windings,  the  circuits  from  brush  to  brush 
consist  of  conductors  influenced  by  all  the  poles,  so  that  the  electromotive  forces  generated  in  the  two 
circuits  are  necessarily  equal,  a  feature  that  may  prove  advantageous  when  the  depth  of  air-gap  is  so 
small  that  any  slight  eccentricity  of  the  armature  affects  the  magnetic  flux  at  the  different  poles. 

In  the  "  long-connection "  type  of  two-circuit  gramme  winding,  the  two  circuits  from  brush  to  brush 
consist  of  conductors  influenced  by  only  one-half  of  the  poles,  so  that  the  electromotive  forces  generated 
in  the  two  circuits  are  unequal,  unless  the  sum  of  the  lines  at  the  poles  of  the  same  sign  is  equal  to  the 
sum  of  the  lines  at  the  poles  of  the  opposite  sign.  In  magnetic  circuits  of  ordinarily  good  design  this 
condition  is  fulfilled  even  though  the  fluxes  at  the  different  poles  are  unequal.  So  the  winding  is  prac- 
tically as  good  as  the  "  short-connection "  winding,  and  possesses  certain  other  advantages  stated  in  the 
text,  that  make  its  use  preferable. 

For  armatures  the  outputs  of  which  are  so  great  that  several  sets  of  collecting  brushes  are  required, 
these  windings  possess  the  same  disadvantages  as  two-circuit  drum  windings,  a  discussion  of  which  is  to 
be  found  under  that  caption. 

1  Called  "short-connection"  type  because  coils  in  adjacent  fields  are  connected  together.  This  distinguishes  it  from  the 
"long-connection"  type,  in  which  coils  twice  as  far  apart  are  connected  together. 


24  ARMATURE   WINDINGS   OF   ELECTRIC   MACHINES.  [CHAP.  in. 

Figure  12  represents  one  of  the  most  practicable  two-circuit  windings  for  multipolar-ring  armatures. 
It  may  be  designated  as  the  long-connection  type  of  the  two-circuit  gramme  winding,  and  one  of  its  chief 
advantages  is,  that  no  great  differences  of  potential  exist  between  adjacent  coils. 

In  the  figure  is  shown  the  case  of  a  four-pole,  two-circuit,  single-wound,  long-connection  ring  armature. 
In  the  position  chosen,  the  circuits  through  the  armature  are,  — 

_  f  11     4    12    5    13     6     14 1 
.29       1     8     15     7 

Coils  3  and  10,  in  series,  are  at  this  instant  short-circuited  by  the  negative  brush.  A  little  later,  coils 
7  and  15  will  be  short-circuited  by  the  positive  brush.  When  this  occurs,  the  negative  brush  will  bear  upon 
the  middle  of  a  segment. 

The  number  of  commutator  segments  is  equal  to  the  number  of  coils,  and  must  be  odd  for  armatures  with 
an  even  number  of  pairs  of  poles ;  but  may  be  odd  or  even  for  armatures  with  an  odd  number  of  pairs  of  poles. 
The  relation  that  must  subsist  in  two-circuit,  multipolar-ring,  long-connection  windings,  between  the  number 
of  coils  (»)  and  the  number  of  poles  (n),  is,  — 

— n     +  1 

where  y  =  pitch.  (The  pitch  is  the  number  of  coils  tp  be  advanced  through  in  arranging  the  end  connections. 
In  the  diagram,  for  instance,  the  pitch  y  =  7,  and  the  end  of  coil  1  is  joined  to  the  beginning  of  coil  1  +  7  = 
8;  the  end  of  8  to  the  beginning  of  8  +  7  =  15;  the  end  of  15  to  the  beginning  of  15  +  7  =  22  (or  7),  etc.) 
Mr.  Gisbert  Kapp  has  prepared  the  following  table  for  two-circuit,  multipolar-ring,  long-connection  windings 
by  substituting  numerical  values  for  n  in  the  above  formula :  — 

TWO-CIRCUIT,   MuLTIPOLAK-RlNG,  LONG-CONNECTION  WINDINGS. 

MACHINE  HAS 

4  poles        6  poles        8  poles        10  poles        12  poles        14  poles 
The  number  of  coils  must  be  equal  to        2y  ±1         3y  ±  1        4  y  ±  1          5y  ±  1  6y  ±1  7  y  ±1 

For  two-circuit,  multipolar-rm^r  machines  with  long-connection  windings,  ?/,  the  pitch,  may  be  any  integer. 
(Note  that  these  conditions  do  not  hold  for  drum  windings.) 

Mr.  Kapp  has  also  prepared  the  following  table,  showing  the  practicable  choice  of  angular  distances 
between  brushes  in  these  two-circuit,  multipolar  windings :  — 

NUMBER  OF  POLES.  ANGULAR  DISTANCE  BETWEEN  BRUSHES. 

2  180 

4 

6 

8 
10 
12 

14  25.7  77  128  180 

16  22.5  67.5  112  158 

18  24,  60  100  140  180 

20  54  90  126  162 

The  smaller  possible  angles,  namely,  20°  for  18  poles,  and  18°  for  20  poles,  are  in  practice  too  small  to  be 
admissible,  and  are,  therefore,  not  given  in  the  table. 


90 

60 

180 

45 

135 

36 

108 

180 

30 

90 

150 

25.7 

77 

128 

22.5 

67.5 

112 

3-6- 

60 

100 

ll 

54 

90 

M 

Fig.  1  2 
TWO  CIRCUIT,  SINGLE  WINDING, 


V 


Fig-.  1  3 
TWO  CIRCUIT,  SINGLE  WINDING. 


CHAI-.  in.]  TWO-CIRCUIT,  SINGLE-WOUND,  MULTIPOLAR   RINGS.  27 


Figure  13  represents  a  two-circuit,  single-wound,  long- 
connection,  ten-pole  ring  armature.  Substituting  in  the 
formula  for  the  number  of  coils 


the  pitch,  y  =  10,  and  the  number  of  poles,  n  =  10,  gives  «  = 
J*°-  •  10  ±  1  =  51  or  49.  51  coils  are  taken  in  this  case.  The 
end  of  coil  1  is  joined  to  the  beginning  of  coil  1  +  10  =  11; 
the  end  of  11  to  the  beginning  of  21,  etc. 

The  brushes  are  shown  180°  apart,  and  at  the  position 
given  the  negative  brush  short-circuits  the  coils  9,  19,  29,  39, 
and  49.  The  circuits  through  the  armature  are,  — 

f    8-18-28-38-48-  7-17-27-37-47-6-16-26-36^16-5-15-25-35-45-4-14-24  j 
i  51  )_iO-30-2<  i-l  (  1-51-11-31-21-11-1-42-32-22-12-2-43-33-23-13-3-44-34  I 

This  diagram  and  table  show  very  clearly  that  with  an 
odd  number  of  pairs  of  poles  and  an  odd  number  of  coils,  an 
odd  number  of  coils  are  short-circuited  at  one  time,  so  that, 
as  the  total  number  of  coils  is  odd,  an  even  number  is  left 
to  be  divided  between  the  two  armature  circuits,  which  are, 
therefore,  equal.  Referring  back  to  Fig.  12,  it  will  be  seen 
that  in  the  case  of  an  even  number  of  pairs  of  poles,  an  even 
number  of  coils  are  short-circuited,  and  as  the  total  number 
of  coils  is  necessarily  odd,  an  odd  number  remains  to  be 
divided  between  the  two  armature  circuits,  so  that  these  are 
necessarily  unequal. 


UNIVERSITY 


28  ARMATUKE    WINDINGS   OF   ELECTIUC   MACHINES.  [CHAP.  in. 


If,  however,  in  Fig.  13  the  brushes  are  put  108°  apart 
instead  of  180°,  coil  24  would  be  taken  from  the  cir- 
cuit given  in  the  upper  line  of  numbers  and  put  in  the 
other  circuit.  There  would  then  be  24  coils  in  one  circuit, 
and  22  in  the  other,  instead  of  23  in  both.  With  the  large 
number  of  coils  used  in  practice,  however,  these  slight  in- 
equalities cause  no  trouble. 

If  y  were  chosen  odd,  9  for  instance,  s  would  equal  46 
or  44. 

8=1- y  ±1  =  ^-9  ±1=46  or  44. 

4  _ 

This  is  in  accordance  with  the  observation  made  above, 
that  in  the  case  of  an  odd  number  of  pairs  of  poles  the 
number  of  coils  may  be  even.  The  diagram  for  this  case 
is  given  in  Fig.  14,  where  8  =  46,  w  =  10,  «/  =  9.  In  the  posi- 
tion shown,  coils  8,  17,  26,  35,  and  44  are  short-circuited 
by  the  negative  brush,  and  coils  31,  40,  3,  12,  and  21  by  the 
positive  brush.  The  circuits  through  the  armature  are,  — 

_  (    7-16-25-34-43-  6-15-24-33-42-5-14-23-32-41-4-13-22  ] 
1  45-30-27-18-  9-46-37-28-19-10-1-38-29-20-11-2-39-30  i   H 

giving,  as  in  Fig.  13,  two  equal  paths  through  the  arma- 
ture. 


Fig.  1  4 
TWO  CIRCUIT,  SINGLE  WINDING. 


Fig.  15 
TWO  CIRCUIT,  SINGLE  WINDING. 


CHA1'.   Ill  ] 


TWO-CIRCUIT,   SINGLE-WOUND,  MULTIPOLAE   KINUS, 


In  Fig.  15  is  given  a  winding  that  has  been  used  in 
practice  with  considerable  success,  owing  partly  to  the 
extreme  regularity  of  all  connections,  and  still  more  to  the 
fact  that  it  involves  the  use  of  twice  as  many  commutator 
segments  as  coils.  Only  one  coil  in  series  is  short-circuited 
at  each  brush,  and  the  volts  per  segment  are  one-half  what 
they  would  be  in  the  unmodified  long-connection  winding. 
The  number  of  coils  to  be  used  is,  as  in  the  unmodified  wind- 


ing, «  =  ?  •  y  ±  1.     Thus,  in  Fig.  15,  »  =  4,  y  =  9,  s  = 

-j  — 

=  19.     Coil  1  is  connected  to  coil  10,  etc. 


9  +  1 


It  will  also  be  noted  that  those  segments 


'3CiO' 


2 


from  each 


other  are  connected  together.     The  number  of  segments  = 

~360~1° 
-  •  s,  of  which  -,  at  distances  of    ^~    from  each  other,  are 

connected  together.  If  every  other  one  of  the  radial  connec- 
tions from  the  coils  to  the  commutator  are  discarded,  the 
winding  becomes  once  more  the  plain,  long-connection,  two- 
circuit,  gramme  winding. 

At  the  position  shown,  coil  13  is  short-circuited  by  the 
negative  brush,  and  the  circuits  through  the  armature  are,— 

3-12-2-11-1-10-19-  9-18 
4-14-5-15-4-1G-  7-17-  8 


32  ABMATUKE   WINDINGS   OF   ELECTRIC   MACHINES.  [OHAP.  in. 

Figure  16  is  an  application  of  the  same  type  of  winding  to  a  six-pole  gramme  ring.  w  =  6,  #  =  6, 
s  =  ^y  ±  1  =  |  •  6  +  1  =  19.  There  are  19xf  =  57  segments.  All  segments  distant  from  each  other  by 

—=120°  should  be  connected  together.     Some  of  the  cross-connections  are  shown  inside  the  armature. 

ft 

2 

At  the  position  shown,  coil  12  is  short-circuited  by  the  positive  brush.  The  circuits  through  the 
armature  are  — 

I    9_3_i6_iO-4-17-ll-  5-18  } 
\  15-2-  8-14-1-  7-13-19-  6  J 

If  the  connections  shown  inside  the  commutator,  together  with  one-third  of  the  segments,  had  been 
omitted,  there  would  have  been  an  unequal  distribution  of  potential  about  the  commutator.  Between  two 
segments  would  be  found  a  certain  voltage,  V,  and  between  the  next  two  2  V;  then  V  again,  etc. 


If  it  should  be  desirable  to  diminish  the  number  of  commutator  segments  to  one-half  the  number  of 
coils,  it  may  be  done  by  the  method  of  connection  shown  in  Fig.  17,  page  34,  which  will  be  recognized  at  once 
as  the  multipolar  ring  counterpart  of  the  two-circuit  winding  as  applied  to  multipolar  drums.  This  winding 
will  be  referred  to  as  a  "  short  connection,"  two-circuit  gramme  winding.  In  the  "  long-connection  "  type, 
examples  of  which  have  just  been  given,  connection  has  been  made  between  coils  situated  in  fields  of  like 
polarity.  But  in  the  "short-connection"  type,  connection  is  made  between  coils  in  adjacent  fields.  Both 
methods  are  feasible  in  ring  windings,  because  the  two  ends  of  a  coil  located  at  a  certain  'point  of  the 
periphery  are  accessible  for  connection  at  the  commutator  end  if  desired,  but  in  drum  windings  only  one 
end  of  a  conductor  located  at  a  given  point  of  the  periphery  is  accessible  at  the  commutator  end,  the 
other  end  of  the  conductor  being  necessarily  connected  across  at  the  opposite  end  of  the  armature,  and 
in  consequence,  also,  must  be  connected  over  to  a  conductor  in  an  adjacent  field  of  unlike  polarity,  in 
order  that  the  electromotive  force,  which  is,  say,  from  front  to  back  in  the  first  conductor,  may  add 
itself  to  that  in  the  second  conductor,  which  must  therefore  be  from  back  to  front;  that  is,  the  second 
conductor  must  be  situated  in  a  field  of  opposite  polarity.  Thus  there  are  two  sub-classes  of  two-circuit, 
multipolar  ring  windings,  in  the  first  of  which  (the  "  long-connection "  winding)  coils  in  fields  of  like 
polarity  are  connected  in  succession,  and  in  the  second  of  which,  as  in  the  two-circuit,  multipolar  drum 
winding,  the  conductors  immediately  succeeding  each  other  are  situated  in  fields  of  opposite  polarity. 

In  this  "  short-connection "  winding  for  two-circuit  multipolar  rings  the  formula  for  determining  the 
proper  number  of  coils,  «,  for  any  number  of  poles,  n,  is  — 

s  =  ny  ±  2, 

where  y,  the  pitch,  may  equal  any  integer,  odd  or  even. 

In  connecting  up  this  "  short-connection  "  type  of  winding  the  following  additional  rule  should  be  borne 
in  mind  in  the  interpretation  and  application  of  the  meaning  of  the  pitch,  y :  The  number  of  coils  in  this 
winding,  being  from  the  formula  always  even,  if  y  is  also  even,  it  is  necessary  in  connecting  up  to  use  as  the 
pitch,  alternately,  ($  —  1)  and  (y  +  1)  instead  of  always  y.  Otherwise,  if  the  coils  are  numbered  successively 


TWO  CIRCUIT,  SINGLE  WINDING 


Fig.  1  7 
TWO  CIRCUIT,  SINGLE  WINDING. 


,  HAP.  in.]  TWO-CIECUIT,   SINGLE-WOUND,   MULTIPOLAK   RINGS.  35 

from  No.  1  on,  the  even-numbered  coils  would  never  be  touched,  if  an  odd-numbered  conductor  were  started 
with,  and  vice  versa.  If  y  were  used  every  time  as  the  pitch,  a  double  winding  would  be  obtained.  This  case 
will  be  treated  later. 

It  may  also  be  well  to  note  that  («/  —  3)  and  (y  +  3)  could  be  used  alternately  as  the  pitch.     It  is  thought, 
however,  that  no  advantages,  and  several  disadvantages,  would  result  from  such  a  choice  of  pitches. 


Figure  17  represents  a  two-circuit,  single-wound,  four-pole  ring  of  the  "  short-connection "  type  just 
described. 

n  =  4,  y  =  8,  s  =  ny  ±  2  =  4  x  8  +  2  =  34. 

This  is  the  case  referred  to  above,  in  which,  s  being  even  and  also  «/,  (j/  —  1)  and  (y  +  1)  must  be  used  alter- 
nately as  the  pitch  in  connecting  up.  The  sequence  of  connections  will  be  seen  in  the  figure  to  be  1, 1  +  7  =  8, 
8  +  9  =  17,  17  +  7=24,  etc. 

Number  of  commutator  segments  =  ^  =  17- 

In  the  position  shown,  coils  7,  14,  23,  and  30,  in  series,  are  short-circuited  at  the  negative  brush,  and  the 
circuits  through  the  armature  are,  — 


_{    5-1 
132-2 


5-12-21-28-  3-10-19-26-1-  8-17-24-33-  6 , 

.25-16-  9-34-27-18-11-2-29-20-13-  4^31-22-15  f 


There  are  14  coils  in  one  path  and  16  in  the  other.  A  little  later,  coils  6,  33,  24,  and  17^  in  series,  will 
be  short-circuited  by  the  positive  brush,  and  coils  7,  14,  23,  and  30  will  take  their  place,  the  circuits  through 
the  armature  then  becoming,  — 

r    7_14_23-30-  5-12-21-28-3-10-19-26-1-  8 1 

I  32-25-16-  9-54-27-18-11-2-29-20-13-4-31-22-15  J 

A  further  inspection  of  the  diagram  will  show  the  unsymmetrical  arrangement  of  the  short-circuited  and 
adjacent  coils,  causing  the  induction  in  some  coils  to  act  in  opposition  to  that  in  others  with  which  it  is  in 
series.  This  is  less  marked  with  large  numbers  of  coils. 


The  chief  disadvantages  of  the  "short-connection"  winding  are  that  adjacent  coils  have  between  them, 
periodically,  the  full  E.M.F.  of  the  armature,  and  that  the  end  windings  are  complicated. 


36  AEMATUEE   WINDINGS   OF   ELECTRIC   MACHINES.  [CHAP.  iir. 


Figure  18  represents  another  two-circuit,  single-wound, 
"short-connection"  gramme  winding,  in  which  s  =  ny±2 
=  4  x  5  ±  2  =  22.  In  this  case  «/,  the  pitch,  is  odd,  and  con- 
sequently the  sequence  of  connections  is  1,  1  +  5  =  6,  6  +  5 
=  11,  11  +  5  =  16,  etc.,  thus  advancing  each  time  by  5,  and 
not,  as  in  the  case  of  Fig.  17,  page  34,  where  y  was  even, 
alternately  by  («/  +  !)  and  (y  —  1).  Corresponding  ends  of 
coils  are  connected  together;  thus,  the  end  of  1  and  the 
end  of  6,  the  beginning  of  6  and  the  beginning  of  11,  etc. 
At  the  position  shown,  coils  5,  10,  15,  and  20  are 
short-circuited  by  the  negative  brush,  and  the  circuits  through 
the  armature  are, — 

f  22-17-12-  7-2-19-14-  9 } 

"  |    3-  8-13-18-1-  6-11-16-21-4  1 

The  winding  is  subject  to  the  disadvantages  noted  in 
connection  with  Fig.  17,  page  34. 

Instead  of  having  the  objectionable  crossings  at  the  ter- 
minals of  the  coils,  as  shown  in  Fig.  18,  page  37,  alternate 
coils  should  be  wound  right  and  left  handedly.  This  would 
only  be  useful  in  cases  where  all  the  connecting  is  done 
at  one  end,  which  should  be  avoided  when  possible. 


Fig.  1  8 
TWO  CIRCUIT,  SINGLE  WINDING. 


Fig.  1  9 
TWO  CIRCUIT,  SINGLE  WINDING. 


CHAP,  in.]  TWO-CIRCUIT,   SINGLE-WOUND,  MULTIPOLAR  RINGS.  39 


Instead  of  connecting  together  in  pairs  coils  lying  in 
fields  of  opposite  polarity,  as  in  Figs.  17  and  18,  adjacent 
coils  may  be  connected  together  as  shown  in  Fig.  19,  and 
these  connected  across  to  coils  in  the  nearest  field  of  like 
polarity.  The  number  of  commutator  segments  is  equal  to 
one-half  of  the  number  of  coils.  The  inherent  identity  of 
this  and  the  "long-connection"  winding  may  be  seen  by 
doing  away  with  the  leads  to  the  commutator  segments, 
and  substituting  leads  from  the  eleven  points  lettered  a, 
b,  o,  d,  etc.  The  result  will  be  a  simple  "  long-connection  " 
gramme  winding,  with  half  as  many  coils  of  twice  as  many 
turns  each. 

Therefore,  the  best  way  of  laying  out  such  a  winding  is 
to  apply  the  rules  for  the  "long-connection"  winding,  and 
make  the  connections  shown  in  Fig.  19,  instead  of  those 
of  the  regular  "  long-connection  "  gramme  winding. 

This  winding  gives  half  as  many  commutator  segments 
as  coils. 

In  the  position  shown,  coils  5,  14,  15,  and  2  are  short- 
circuited  by  the  positive  brush,  and  the  circuits  through  the 
armature  are,  — 

8-21-20-11-10-  1-22-13-12-3  1  > 

9-18-19-  6-  7-16-17-  4 J 


CHAPTER  IV. 

TWO-CIRCUIT,  MULTIPLE-WOUND,  MULTIPOLAR  RINGS. 

THE  next  class  is  that  of  the  two-circuit,  multiple-wound,  long-connection  ring  windings. 
The  general  formula  is,  — 

n 
s=-xy±m, 

where 

8  =  number  of  coils, 

n  =  number  of  poles, 

y  =  pitch, 

m  =  number  of  windings. 

The  "T»"  windings  will  consist  of  a  number  of  independently  re-entrant  windings  equal  to  the  greatest 
common  factor  of  "  y  "  and  "  m." 

Therefore,  when  it  is  desired  that  the  "  m  "  windings  shall  combine  to  form  one  re-entrant  system, 
it  will  be  necessary  that  the  G.C.F.  of  "y"  and  "m"  shall  be  made  equal  tp  1. 

Figure  20  represents  a  two-circuit,  doubly  re-entrant,  double-wound  ring  armature. 

8=26,  n=4,  m=2. 


Greatest  common  factor  of  y  (12)  and  m  (2)  is  2.     Therefore  the  winding  will  be  doubly  re-entrant. 
At  the  position  shown,  coils  24  and  12,  in  series,  are  short-circuited  by  the  negative  brush.     The  circuits 
through  the  armature  are,  — 

{  25-13-1-15-3-17—  \ 
I  26-14-2-16-4-18—  I 

t  10-22-8-2 


1 11-23-9-21-7-19-5  '  H 
40 


Fig.  20 
TWO  CIRCUIT,  DOUBLE  WINDING. 


,Fig.  2  1 
TWO  CIRCUIT,  DOUBLE  WINDING, 


CHAP.   IV.] 


TWO-CIKCUIT,   MULTIPLE-WOUND,  MULTIPOLAE   RINGS. 


43 


Figure  21  represents  a  two-circuit,  singly  re-entrant, 
double-wound  ring  armature. 

In  this  case  y  =  ll,  n  =  4,  and  m  =  2.  8=|xll±2  =  20 
or24.  24  coils  are  taken.  G.C.F.  of  "«/"  and  "m"  being 
1,  the  winding  is  singly  re-entrant. 

In  the  position  given,  coils  9  and  22  are  short-circuited 
at  the  negative  brush,  and  4  and  15  at  the  positive.  The 
circuits  through  the  armature  are,  — 


f  20-7-18-5-16 — - 
1  21-8-19-6-17 


f 11-24-13-2 

1 10-23-12-1-14-3 


44 


ARMATURE   WINDINGS   OF   ELECTRIC    MACHINES. 


[CHAP.  iv. 


Figure    22    represents    another    two-circuit,    singly    re- 
entrant, double-wound  ring  armature. 


=  2,  M=<),  «/  =  7,  s  = 


2  =    x7±2  =  19or  23. 


"y"  and  "?»"  being  prime,  the  winding  is  singly  re- 
entrant. 

At  the  position  shown,  coils  4,  11,  and  18  are  short- 
circuited  at  the  positive  brush,  and  the  circuits  through  the 
armature  are:  — 


f  15-22-6-13-20  1 
1 14-21-5-12-19  I 

8-  1-17-10-3-  1 
7-23-16-  9-2-  I 


Two    two-circuit,   singly   re-entrant,  triple  windings  for 
gramme  rings  are  given  below  without  diagrams :  — 

n»=3,  n=6,  y=7,  *=^xy  ±3=^x7  +  3  =  24. 

Z  i 

The  connections  would  be,  — 

1-8-15-22-5-12-19-2-9-16-23-6-13-20-3-10-17-24-7-14-21 
^t-11-18-1 


m=3,  w=10,  y=10,  8=^x10-3=47. 

1-11-21-31^1^-14-24-31-11-7-17-27-37^7-10-20-30-40-3 
-13-23-33-43-6-16-26-36-46-9-19-29-39-2-12-22-32-^2 
-5-15-25-35-45-8-18-28-38-1 


Fig.  22 
TWO  CIRCUIT,  DOUBLE  WINDING. 


TWO  CIRCUIT,  TRIPLE  WINDING. 


CHAR   IV.] 


TWO-CIRCUIT,   MULTIPLE-WOUND,   MULTIPOLAR   RINGS. 


47 


Figure  23  represents  a  two-circuit,  singly  re-entrant,  triple  winding. 

"m"  and  "y"  being  prime,  the  winding  is  singly  re-entrant. 

In  the  position  shown,  coils  5  and  15,  in  series,  are  short-circuited  by  the  positive  brush.     The  circuits 
through  the  armature  are,  — 

f  22-9-19-6-16 

|  21-8-18— 

120-7-17 


f  12-  2 


11-  1-14-4 
1  10-23-13-3 


The  extreme  irregularity  of  the  various  circuits  in  multiple  is  not  characteristic  of  the   winding,  but  is 
merely  due  to  the  very  small  number  of  coils  chosen.     In  practical  cases  it  would  be  negligible. 


From  the  formula  and  conditions  of  page  40,  and  from  the  examples  just  given,  it  will  be  seen  that  two- 
circuit,  multiple-wound,  ring  windings  may  be  divided  into  the  three  following  cases:  — 

CASE  I.  —  "y"  and  "m"  are  mutually  prime.  This  gives  a  singly  re-entrant  winding  of  "m  "  multiple 
windings. 

Illustration:  —  n  =  4,  y  =  l,  m  =  4,  s  =  |x7+4  =  18. 

Connections  are,  -  l-8-16-4-ll-l»-7-14-3-10-17-6-l»-2-9^1(^5-12-l. 

May  be  expressed  symbolically  as  (OOP). 

CASE  II.  —  "#"  a  multiple  of  "TM."     This  gives  "TO"  independently  re-entrant  windings. 

Illustration  :  — 

w  =  4,  y  =  8,  m=4,  «  =  f  x8+4  =  20. 

Connections  are,  —  1-  9-17-5-13-1 

2-10-18-6-14-2 
3-11-19-7-15-3 

4_12-20-8-16-4 

May  be  expressed  symbolically  as  O  O  O  O- 

CASE  III.  —  "«/"  and  "w"  have  common  factors.     This  gives  a  number  of   independently  re-entrant 
windings,  equal  to  the  greatest  common  factor  of  "  y  "  and  "  m." 
Illustration  :  — 


The  result  is  a  two-circuit,  quadruple  winding  with  two  independently  re-entrant  windings,  because  2  is  the 
greatest  common  factor  of  "  y  "  and  "  m." 

The  connections  are,  — 

1_7_13_3_9_15_5_11_1     and     2-8-14-4-10-16-6-12-2 

May  be  expressed  symbolically  as  ©  ©. 
Case  II.  is  really  a  special  instance  of  Case  III. 

The  above  formula  and  controlling  conditions  will  be  found  to  hold  for  all  numbers  of  poles,  coils,  pitches, 
and  windings  of  the  two-circuit,  long-connection  type  of  gramme-ring  armature  windings. 


48 


AKMATURE  WINDINGS   OF   ELECTRIC   MACHINES 


[CHAP.  iv. 


Figure  24  is  a  two-circuit,  singly  re-entrant  triple  winding 
of  the  type  described  in  connection  with  Figs.  15  and  16, 
which,  it  should  be  remembered,  is  only  a  modification  of 
the  long-connection  type. 


n=4,  «/  = 


=x  10  +  3=23. 


At  the  position  shown,  coil  21  is  short-circuited  at  the 
negative  brush,  and  coils  3  and  4  at  the  positive  brush.  The 
circuits  through  the  armature  are,  — 


8-18-  5 — 
-  |    9-19-  6-16 
—20-  7-17 

22-12-  2-15 
—11-  1-14 
10-23-13 


Figure  24  should  be  compared  with  Figs.  15  and  16. 


Fig.  24 
TWO  CIRCUIT,  TRIPLE  WINDING. 


CHAPTER  V. 

DRUM  ARMATURE  WINDINGS. 

IN  drum  windings,  all  connections  from  bar  to  bar  must 
be  made  upon  the  rear  and  front  ends  exclusively,  it  not 
being  practicable  to  bring  connections  through  inside  from 
back  to  front  as  is  the  case  with  rings.  Consideration  of 
this  limitation  will  show  that  the  two  sides  of  any  one  coil 
must  be  situated  in  fields  of  opposite  polarity,  so  that  the 
electromotive  forces,  generated  in  the  active  conductors  of  a 
coil  by  their  passage  through  their  respective  fields,  shall  be 
in  the  same  direction. 

In  the  case  of  a  drum,  it  should  also  be  noted  that  a  coil 
is  linked  with  the  whole  or  nearly  the  whole  flux  from  one 
pole  piece,  instead  of,  as  in  the  ring  armature,  with  only  one- 
half  of  the  flux. 


BIPOLAR  DRUM  WINDINGS. 

The  winding  of  bipolar  armatures  is  much  less  simple  in 
the  case  of  drums  than  in  that  of  rings,  and  it  will  therefore 
be  necessary  to  give  considerable  attention  to  the  various 
methods  in  which  such  windings  may  be  carried  out. 


51 


52  AEMATUKE   WINDINGS  OF  ELECTKIC   MACHINES.  [CHAP.  v. 


Figure  25  represents  essentially  the  winding  devised  by  von  Hefner- Alteneck.  It  is  used  chiefly  for 
small,  smooth-core,  wire-wound  armatures,  and  the  element  of  the  winding,  represented  in  the  diagram  by  a 
pair  of  face  conductors,  and  a  back  connection  consists  usually,  in  practice,  of  a  coil  of  several  turns,  compar- 
able in  some  respects  to  the  coil  of  the  ring  windings  ;  but  in  the  diagram  only  one  turn  per  coil  will  be 
shown.  This  will  also  be  advantageous,  inasmuch  as  large,  iron-clad,  bar-wound,  multipolar  drum  armatures 
are  derived  from,  and  diagrammatically  are  very  analogous  to,  the  wire-wound,  smooth-core  armatures  now 
under  consideration. 

An  examination  of  Fig.  25  shows  that,  starting  from  a  commutator  segment,  the  winding  proceeds  over 
the  front  end  to  conductor  No.  1 ;  down  No.  1  over  the  back  to  conductor  No.  8,  which,  it  should  be  noted, 
is  adjacent  to  the  conductor  diametrically  opposite  No.  1.  From  No.  8  the  winding  returns  to  the  next 
commutator  segment,  and  is  then  carried  to  conductor  No.  3  (skipping  No.  2,  which  will  later  be  joined 
over  the  back  to  a  conductor  almost  diametrically  opposite  to  it),  down  No.  3,  over  the  back  to  No.  10,  etc. 
From  this  it  is  seen  that  the  "  pitch  "  on  the  back  end  is  7  and  on  the  front  end  is  —  5. 
In  the  position  shown,  the  circuits  through  the  armature  are,  — 

r 10-  3-8-  1-  6-15  I 
"  1    7_14_9_16-11-  2  J 

The  coil  represented  by  the  conductors  13  and  4  is  short -circuited  at  the  positive  brush,  and  coil  12-5  at 
the  negative  brush. 

The  customary  convention  is  adopted  in  the  diagram,  0  indicating  a  current  from  the  observer  into 
the  paper,  and  $  a  current  up  out  of  the  surface  of  the  paper  toward  the  observer. 

A  serious  fault  of  this  winding  is  that  large  differences  of  potential  exist  between  adjacent  conductors  (or, 
usually,  groups  of  conductors).  This  would  be  of  no  importance  with  the  small  numbers  of  conductors 
represented  in  these  diagrams,  but  in  actual  cases,  large  numbers  of  conductors  are  used,  and  are  placed 
close  together  in  order  to  waste  no  available  space. 


Fig.  25 
TWO  CIRCUIT,  SINGLE  WINDING. 


Fig.  26 
TWO  CIRCUIT,  SINGLE  WINDING. 


CHAP,  v.]  DKUM  AKMATUKE   WINDINGS.  55 


Figure  26  gives  the  diagram  of  a  winding  discussed  by 
Swinburne.  Its  characteristic  feature  is  the  use  of  a  small 
pitch  (in  the  figure  the  pitch  at  the  back  end  is  11,  and  at 
the  front  end  it  is  —9),  whereby  the  turns  consist  of  con- 
ductors separated  by  a  much  smaller  angular  distance  than 
in  the  von  Hefner- Alteneck  winding. 

An  advantage  of  this  winding  is  that  there  is  much  less 
crossing  of  the  end  connections  than  is  the  case  where  the 
pitch  is  taken  larger.  Thus  the  difficult  question  of  insula- 
tion at  the  ends  of  the  armature  is  greatly  simplified. 

Still  further,  it  has  been  pointed  out  by  Swinburne  that 
the  demagnetizing  effect  of  the  armature  on  the  field  is 
reduced,  as  may  be  seen  from  the  fact  that  the  currents  in 
the  conductors  in  the  demagnetizing  belt  between  the  pole 
tips,  namely,  23,  24,  25,  and  26,  and  in  7,  8,  9,  and  10,  are 
alternately  in  opposite  directions,  and  thus  neutralize  each 
other. 

A  serious  disadvantage  is  that  the  short-circuited  coils, 
6-27  and  11-22,  are  considerably  removed  from  the  neutral 
line.  This,  together  with  the  fact  that  the  counter-electro- 
motive forces  present  in  several  conductors  of  the  circuit 
between  brushes  detract  from  the  volts  per  unit  of  length  of 
armature  wire,  reduces  to  rather  small  limits  the  extent  to 
which  such  connecting  over  short  chords  should  be  carried. 

In  the  position  shown,  the  circuits  through  the  armature 
are, — 

_  i  20-  9-18-  7-16-  5-14-  3-12-  1-10-31-  8-29  1 
"  1 13-24-15-26-17-28-19-30-21-32-23-  2-25-  4  J 


07  THU 

[U3IVBRSITT] 


56  ARMATURE   WINDINGS   OF   ELECTRIC   MACHINES.  [CHAP.  v. 


In  Fig.  27  it  will  be  seen  that  the  number  of  coils  is  odd 
(in  the  two  preceding  diagrams  it  was  even),  with  the  result 
that  the  two  active  sides  of  such  coils  may  now  be  diametri- 
cally opposite. 

This  would  not,  however,  usually  be  advisable,  as  it 
makes  many  more  crossings  at  the  ends,  and  therefore  in- 
creases the  difficulty  of  insulating. 

Some  advantage  results  from  bringing  the  short-circuited 
coil  (in  the  figure,  coil  24-9  is  short-circuited  by  the.  nega- 
tive brush),  exactly  in  the  neutral  line,  this  being,  of  course, 
only  possible  when  the  conductors  forming  its  active  sides 
are  diametrically  opposite. 

The  circuits  through  the  armature  in  the  position  shown 
are, — 

f 22-  7-20-  5-18-  3-16-1-14-29-12-27-10-25  1 
1 11-26-13-28-15-30-17-2-19-  4-21-  6-23-  8  J 

The  pitch  on  the  back  end  is  15,  and  on  the  front  end  it 
is  -13. 

Owing  to  the  number  of  segments  being  odd,  only  one 
coil  is  short-circuited  at  once,  unless  wide  brushes  are  used. 


Fig.  27 
TWO  CIRCUIT,  SINGLE  WINDING. 


Fig.  28 
TWO  CIRCUIT,  SINGLE  WINDING, 


CHAP,  v,]  DEUM  AEMATUHE  WINDINGS.  59 


In  Fig.  28  there  is  also  an  odd  number  of  coils  (and 
therefore  an  odd  number  of  commutator  segments).  But 
instead  of  connecting  over  the  back  from  No.  1  to  No.  16 
(the  conductor  diametrically  opposite  No.  1)  as  in  Fig.  17, 
connection  is  made  over  the  back  from  No.  1  to  No.  14, 
then  over  the  front  to  No  3,  etc  ,  the  pitch  at  the  back 
end  being  13,  and  on  the  front  end  —11.  It  is,  therefore, 
a  mild  form  of  the  Swinburne  chord  winding,  as  described 
in  connection  with  Fig,  26.  The  end  connections  are 
better  distributed  and  have  fewer  crossings  than  was  the 
case  in  Fig.  27,  where  diametrically  opposite  conductors 
were  connected  into  coils. 

In  the  position  shown,  coil  22-9  is  short-circuited  at 
the  negative  brush,  and  the  circuits  through  the  armature 
are,  — 

11-24-13-26-15-28-17-30-19-  2-21-  4-23-  61 
20-  7-18-  5-16-  3-14-  1-12-29-10-27-  8-25  I 


60  ARMATURE   WINDINGS   OF   ELECTRIC   MACHINES.  [CHAI-.  v. 


In  Fig.  29  the  winding  is  carried  on  over  a  still  shorter  chord,  the  pitch 
at  the  back  end  being  11  and  at  the  front  end  —9. 

It  is  very  instructive  to  compare  Figs.  27,  28,  and  29,  all  of  which  have 
30  face  conductors  (15  coils).  But  in  Fig.  27  diametrically  opposite  con- 
ductors are  connected  over  the  back,  the  back  pitch  being  15.  Figure  28 
is  a  weak  chord  winding,  the  back  pitch  being  13.  Figure  29  is  a  decided 
chord  winding,  the  back  pitch  being  11.  The  points  to  be  compared  are 
the  positions  of  the  short-circuited  conductors  with  reference  to  the  neutral 
line  ;  the  amount  of  neutralizing  of  the  effect  of  the  demagnetizing  belt 
between  pole  tips,  and  the  comparative  amount  of  crossing  of  connectors 
at  the  ends. 

In  Fig.  27  it  was  shown  that  diametrically  opposite  conductors  could 
be  connected  into  coils  if  the  number  of  coils  were  chosen  odd. 

The  same  object  may  be  attained  with  an  even  number  of  coils  by 
winding  them  in  two  layers  instead  of  in  one  layer,  as  has  been  the  case 
in  all  the  heretofore  described  bipolar  drum  armatures. 

It  should  be  again  noted  that  the  term  "  conductors  "  is  used  in  these 
explanations,  although  "groups  of  conductors  "  could  often  be  substituted 
therefor  in  small,  smooth-core,  wire-wound  armatures. 

Thus  the  set  of  "  one-layer  windings,"  just  described,  are  those  in 
which  "  conductors "  or  "  groups  of  conductors "  are,  in  the  completed 
winding,  arranged  in  one  layer,  although  the  individual  wires  of  such  a 
group  may  optionally  occupy  one  or  several  layers.  In  the  same  way, 
the  two-layer  windings  now  to  be  described  are  those  in  which  the  com- 
pleted winding  consists  of  "  conductors "  or  "  groups  of  conductors " 
arranged  in  two  layers,  although  the  actual  depth  of  individual  wires 
may,  when  desirable,  be  greater  than  two. 


F\g.29 
TWO  CIRCUIT,  SINGLE  WINDING. 


o. 


13 


O 


10 


Fig.  30 
a,b, c  and  d. 


CHAP,  v.]  DKUM   AKMATUKE   WINDINGS.  63 


In  Fig.  30,  diagrams  a  and  b  represent  a  single-layer 
bipolar  drum  winding  with  an  odd  number  of  coils,  in 
which  diametrically  opposite  conductors  are  connected 
together  into  coils.  In  diagram -a  the  first  half  of  the 
winding  is  carried  out  and  proceeds  from  a  commutator 
bar  to  conductor  No.  1,  to  8,  to  3,  to  10,  to  5,  to  12,  to  7, 
to  14,  and  is  then  ready  for  the  second  half.  It  will  be 
seen  that  at  this  stage  only  every  other  coil  is  connected 
up,  and  that  only  one-half  of  the  commutator  segments 
are  utilized.  Diagram  b  shows  the  winding  completed. 
This  winding,  which  is  of  the  type  shown  in  Fig.  27,  is 
given  here  for  comparison  with  the  two-layer  winding 
shown  in  diagrams  c  and  d.  In  Fig.  c  it  will  be  seen 
that  the  first  half  is  exactly  the  same  as  the  first  half 
of  the  one-layer  winding  (except  that  it  contains  eight 
conductors  instead  of  seven),  and  at  the  completion  of 
the  first  half  all  the  conductors  of  the  lower  layer  are 
connected  up  in  the  order  1-9-3-11-5-13-7-15,  and  only 
one-half  of  the  commutator  segments  are  connected  in. 
The  coils  remaining  for  the  second  half,  instead  of  lying 
between  those  of  the  first  half,  occupy  an  outer  layer. 
Diagram  d  shows  the  completed  winding,  with  all  the 
coils  and  commutator  segments  utilized. 


64  ARMATURE   WINDINGS   OF   ELECTRIC   MACHINES.  [CHAP.  v. 


Figure  31  represents  a  two-layer  winding  with  thirty-two  conductors, 
with  diametrically  opposite  conductors  connected  into  coils  over  the 
back  end. 

These  back-end  connections  are  not  shown,  because  they  would  interfere 
with  the  clearness  of  the  diagram.  The  connections  are  1-17-3—19-5-21, 
etc.  In  the  position  shown,  coil  25—9  is  short-circuited  at  the  negative 
brush  and  20-10  at  the  positive  brush,  and  the  circuits  through  the 
armature  are,  — 

f  23-  7-21-  5-19-  3-17-1-16-32-14-30-12-28  1 
1 11-27-13-29-15-31-18-2-20-  4-22-  6-24-  8  I 

» 

It  will  be  seen  from  this  table  that  maximum  difference  of  potential 
exists  between  conductors  lying  directly  over  each  other  in  different 
layers,  such  as  27  and  28,  or  7  and  8.  But  adjacent  conductors  have 
only  small  differences  of  potential ;  therefore,  the  two  layers  should  be 
carefully  insulated  from  each  other. 

It  is  an  advantage  to  have  the  conductors  25-9  and  26-10  of  the  two 
short-circuited  coils  all  situated  on  one  diameter,  as  they  may  therefore 
be  brought  diametrical,  and  therefore  are  capable  of  being  short-circuited 
more  nearly  in  the  neutral  position. 

A  disadvantage  of  the  winding  is  that,  one-half  being  wound  exclu- 
sively in  the  lower  layer  and  the  other  half  in  the  upper,  they  have 
unequal  lengths  and  different  peripheral  speeds,  and  in  those  recurring 
positions  in  which  the  two  circuits  through  the  armature  consist  respect- 
ively of  the  lower  and  the  upper  layer,  the  condition  will  be  unbalanced. 

In  practice,  however,  it  is  frequently  found  expedient  to  use  this  con- 
nection because  of  the  ease  of  winding,  the  inequality  being  made  as 
small  as  possible.  It  will  be  shown  later  how  this  inequality  may  be 
obviated ;  the  winding  will  be,  however,  less  easy  to  execute. 


Fig.  31 
TWO  CIRCUIT,  SINGLE  WINDING. 


Fig.  32 
TWO  CIRCUIT,  SINGLE  WINDING 


CIIAP.  v.]  DEUM   AEMATURE   WINDINGS.  67 


In  Fig.  32  the  winding  is  of  the  Swinburne  type,  being  connected  over  the  ends 
along  a  short  chord.  Thus,  starting  from  a  commutator  segment,  it  passes  down 
No.  1,  over  the  back  to  No.  13,  over  the  front  to  No.  3,  and  so  on  through  3,  15,  5, 
17,  7,  19,  9,  21,  11,  23  ;  but  coming  over  the  front  from  23  it  would  naturally  go  to 
13  of  the  lower  layer.  This,  however,  is  already  used,  so  the  winding  continues  by 
No.  14,  which  is  directly  over  No.  13  in  the  top  layer,  and  then  on  through  25—16- 
27-18-29-20-31-22.  From  22  it  would  naturally  go  to  No.  1,  but,  as  the  winding 
is  not  yet  completed,  it  must  go  instead  to  No.  2,  which  is  directly  over  No.  1,  and 
then  proceed  from  2  through  24-4-26-6-28-8-30-10-32-12,  and  then  it  closes  on 
itself  at  No.  1.  This  winding  is  not  at  all  difficult,  because,  although  the  lower 
layer  is  not  entirely  completed  before  beginning  to  wind  the  upper  layer,  yet  in  that 
part  of  the  armature  on  which  it  is  desired  to  wind  the  upper  layer,  the  lower  layer 
is  entirely  completed,  and  for  quite  a  distance  beyond,  so  that  there  would  be  no 
trouble  in  inserting  the  necessary  insulation,  etc. 

In  the  position  shown,  coil  28-8  is  short-circuited  at  the  positive  brush,  and  coil 
23-11  at  the  negative  brush.  It  is  a  disadvantage  to  Jiave  the  short-circuited  coils 
so  far  from  the  neutral  line. 

The  circuits  through  the  armature  in.  the  given  position  are,  — 

f  21-  9-19-  7-17-  5-15-  3-13-1-12-32-10-30  ] 
1 14-25-16-27-18-29-20-31-22-2-24-  4-26-  6  ! 

It  will  be  seen  that  in  this  armature  there  can  be  no  position  in  which  one  layer 
belongs  exclusively  to  one  circuit  and  the  other  to  the  other  circuit.  Therefore 
the  discrepancy  in  lengths  and  peripheral  speeds  of  the  two  circuits  through  the 
armature  will,  at  the  most  unfavorable  moment,  be  less  than  when  diametrically 
opposite  conductors  are  connected  into  coils.  The  winding  has,  in  common  with  all 
chord  windings,  the  advantage  of  less  crossings  of  the  end  connections.  The  diagram 
shows  particularly  well  the  absence  of  demagnetizing  action  in  the  zone  of  con- 
ductors between  pole  tips. 

If,  in  Fig.  32,  page  66,  conductor  No.  1  had  been  connected  over  the  back  to 
No.  15  instead  of  to  No.  13,  it  would  still  have  been  a  chord  winding,  but  witli 
somewhat  less  marked  characteristics  than  that  of  Fig.  32.  All  the  advantages  and 
disadvantages  would  have  been  on  a  smaller  scale. 


08  AttMATUJRE   WINDINGS   OF   ELECTRIC   MACHINES.  [CHAP.  v. 


Figure  33  represents  a  winding  in  which  coils  of  the 
outer  and  inner  layer  are  alternately  connected.  The  rear- 
end  connections  are  not  drawn,  but  are  diametrical.  Thus 
the  series  is  1-15-4-18-5-1 9-8-22-9-23-12-26-1 3-27-1  <i-2- 
17_3_20-6-21-7-24-10-25-ll-28-14-l.  This  makes  both 
circuits  through  the  armature  of  very  nearly  equal  length 
and  of  very  nearly  equal  average  peripheral  speed. 

In  the  position  shown,  coil  21-7  is  short-circuited  by  the 
positive,  and  22-8  by  the  negative  brush.  The  circuits 
through  the  armature  are,  — 

{  19-  5-18-  4-15-  1-14-28-11-25-10-24  1 
-    9-23-12-26-13-27-16-  2-17-  3-20-  6  J 

For  this  winding  to  be  regular,  the  number  of  conductors 
must  be  an  odd  multiple  of  4. 

Other  bipolar  drum  windings  have  been  proposed  by 
Hering,  Western  Electric  Company,  and  others,  each  of 
which  possesses  certain  special  advantages.  It  might  be 
well  especially  to  consult  an  article  by  Hering  in  "  Electri- 
cian and  Electrical  Engineer,"  Vol.  4,  1885,  p.  423,  and 
Vol.  5,  1886,  p.  84. 


Fig.  33 
TWO  CIRCUIT,  SINGLE  WINDING. 


N 


N 


Fig.  34 
S\X  CIRCUIT,  SINGLE  WINDFNG. 


CHAPTER  VI. 


MULTIPLE-CIRCUIT,  SINGLE-WOUND,  MULTIPOLAR  DRUMS. 

FOR  multiple-circuit,  multipolar  drums,  the  condition  to  be  fulfilled  to  make  the  winding  re-entrant  is 
that  there  shall  be  an  even  number  of  bars.  The  pitch  at  one  end  of  the  armature  must  exceed  that  at 
the  other  end  by  2  (for  single  windings),  each  of  these  pitches  being  odd.  If  n  is  the  number  of  poles 

Q 

and   C  the  number  of  face  conductors,  the  average  pitch  should  not  differ  much  from  —  ;  for  if  it  is  much 

n 

less,  two  successive  conductors  will  often  lie  under  the  same  pole  piece,  and  their  induced  electromotive 
forces  will  be  in  opposition  to  each  other,  whereas  they  should  be  additive.     If  the  average  pitch  is  much 

0 
greater  than  —  ,  the  cross-connections  will  be  unnecessarily  long,  and  the  armature  resistance  and  cost  of 

tli 

copper  unnecessarily  high.      Suppose  a  preliminary  calculation  for  a  single-layer,  six-pole  machine  shows 

The  two-end   pitches  must  both 


0     49 

that  about  49  conductors  are  required,  it  will  be  seen  that  —  =  —=8.17. 

n      6 


be  odd  numbers,  and  must  differ  by  2.  Therefore,  take  7  and  9.  The  mean  pitch  is  8.  The  condition  to  be 
fulfilled  by  the  total  number  of  conductors  is  that  it  shall  be  an  even  number.  Let  it  be  50. 

This  case  is  shown  in  Fig.  34.  In  this  diagram  the  radial  lines  represent  the  face  conductors.  The  con- 
necting lines  on  the  inside  represent  the  end  connections  at  the  commutator  end,  and  those  on  the  outside  represent 
the  end  connections  at  the  pulley  end.  The  brushes  are  placed  inside  the  commutator  for  convenience. 

At  the  position  shown,  the  conductors  without  arrow-heads  are  short>circuited.  The  circuits  through 
the  armature  are,  — 

6-49-  8-  1-10- 
45_  2-43-50-ll^t 

|  22-15-24-17-26-1 
1 11-18-  9-16-  7-14 


_  i  40-33-42-35^4-37 

I  29-36-27-34-25-32-23-30 

The  front-end  pitch  is  ?/  =  9,  and  the  back-end  pitch  is  y=—1. 


71 


72  ARMATUKE    WINDINGS   OF   ELECTK1C    MACHINES.  [OUAP.  vi. 


If  the  pitches  had  been  taken  7  and  —5  instead  of  9  and  —7,  retaining  the  same 
number  (50)  of  face  conductors,  the  diagram  given  in  Fig.  35  would  have  been  the 
result.  This,  it  will  be  seen,  is  an  application  of  the  chord  winding  to  a  multipolar  arma- 
ture. The  current  in  the  conductors  in  the  neutral  zone  is  alternately  in  opposite  direc- 
tions, so  that  the  demagnetizing  action  of  the  armature  is  small.  The  end  connections 
are  shorter,  occupying  less  room  and  reducing  the  armature  resistance  and  cost  of  copper. 
The  short-circuited  conductors  are,  however,  at  some  distance  from  the  neutral  lines,  and, 
although  the  electromotive  forces  in  each  pair  will  partly  neutralize  each  other,  it  would 
be  advisable,  in  cases  where  such  chord  windings  are  adopted,  to  have  as  great  distances 
between  pole  tips  as  other  circumstances  permit. 

In  the  given  position,  the  short-circuited  conductors  are  4-49,  12-7,  20-15  28-23,  38- 
33,  46-41.  The  armature  circuits  are, — 


-1 


G-  1-  8-  3-10- 
47_  2-45-50-43-4 


J  22-17-24-19-26-21 
"  i  13-18-11-16-  9-14 

-I 


40-35-42-37-44-39- 
31-36-29-34-27-32-25-3 


The  front-end  pitch  is  y  =  1,  and  the  back-end  pitch  y——b. 

If  it  should  be  considered  desirable  to  have  all  the  paths  through  the  armature  contain 
exactly  the  same  number  of  conductors,  then  the  number  of  face  conductors  should  be 
chosen  a  multiple  of  the  number  of  poles.  But  with  a  large  number  of  conductors  this 
would  generally  not  be  an  important  consideration. 

In  modern  practice  the  conductors  in  large  multipolar  machines  frequently  consist  of 
bars  arranged  in  slots.  The  end  connections  then  become  strips  arranged  in  two  or  more 
spiral  layers  at  each  end.  If  there  were  only  one  conductor  per  slot,  two  layers  at  each 
end  would  still  be  necessary,  as  it  would  be  the  same  as  if  the  lower  conductors  were 
brought  up  side  of  the  upper  conductors,  and  every  other  conductor  would,  therefore,  as 
before,  be  connected  over  in  an  opposite  direction  from  its  neighbor. 

For  multiple-circuit,  single-wound  armatures  there  may  be  any  even  number  of  con- 
ductors per  slot,  and  any  number  of  slots.  No  new  diagrams  are  necessary  to  show  the 
cases  of  two  or  more  conductors  per  slot,  as  Figs.  34  and  35  may  be  interpreted  as  having 
twenty-five  slots  and  two  conductors  per  slot,  in  which  case  odd-numbered  conductors 
may  be  considered  to  belong  to  the  upper  layer,  and  even-numbered  conductors  to  the 
lower  layer.  Connection  is  always  made  between  odd  and  even  numbered  conductors,  the 
pitch  being  always  odd.  The  front-end  and  back-end  pitches  must  differ  by  2,  and  must 
have  opposite  signs. 


N 


32y 


18 


N 


281 


Fig.  35 
SIX  CIRCUIT,  SINGLE  WINDING. 


N 


Fig.  36 
SIX  CIRCUIT,  SINGLE  WINDING. 


vi.]  MULTIPLE-CIRCUIT,   SINGLE-WOUND,   MULTIPOLAR   DRUMS.  75 


Figure  36  represents  a  six-circuit,  single-wound,  drum  winding  with  eighty  con- 
ductors. The  number  of  conductors  is  purposely  taken  large,  so  that  a  study  of  the 
diagram  and  winding  table  may  show  the  magnitude  of  the  differences  of  potential  in 
neighboring  conductors. 

At  the  given  position,  conductors  75-6,  9-20,  21-32,  35-46,  49-60,  and  61-72  are 
short-circuited  at  the  brushes.  The  circuits  through  the  armature  are, — 

_  i    8-77-10-79-12-  1-14-  3-1(5-  5-18-  7- 
t  73-  4-71-  2-159-80-67-78-65-76-63-74 

_  J  34-23^36-25-38-27-40-29-42-31-44-33 
"  {  19-30-17-28-15-26-13-24-11-22 


r  62-51-64-53-66-55-68-57-70-59 

"  \  47_58-15-56-43-54-41-52-39-50-37-4i 

An  inspection  of  the  above  table  will  show  that  the  full  difference  of  potential 
exists  at  recurring  intervals  between  each  pair  of  sequential  conductors,  such  as  7  and 
8,  or  47  and  48.  In  practice,  such  conductors  will  often  consist  of  two  bars  lying  one 
above  the  other  in  the  same  slot.  This  shows  that  such  upper  and  lower  layers  in  a 
slot  should  be  carefully  insulated.  On  the  other  hand,  alternately  sequential  conductors, 
as  5  and  7,  or  47  and  45,  have  between  them  only  the  small  difference  of  potential  of  two 
conductors  in  series;  so  that,  in  practice,  where  such  conductors  usually  belong  both  to 
the  upper  or  both  to  the  lower  layer  of  the  same  slot,  comparatively  thin  layers  of 
insulation  suffice.  For  instance,  it  is  often  the  case  in  multiple-circuit  windings  that 
there  are  four  conductors  per  slot,  arranged  two  wide  and  two  deep.  This  case  would 
require  that  the  horizontal  layer  of  insulation  between  conductors  should  be  much  thickei 
than  the  vertical  layer. 

For  this  class  of  windings  (multiple-circuit,  single-wound  drums)  a  formula  is  super- 
fluous, and  the  following  summary  of  conditions  will  suffice :  — 

There  may  be  any  even  number  of  conductors,  except  that  in  ironclad  windings  the 
number  of  conductors  must  also  be  a  multiple  of  the  number  of  conductors  per  slot. 

The  front  and  back  pitches  must  both  be  odd,  and  must  differ  by  2 ;  therefore  the 
average  pitch  is  even. 

ft 

The  average  pitch  "y"  should  not  be  very  different  from  -,  where  c  =  number  of  con- 

Q 

ductors,  and  n  =  number  of  poles.     For  chord  windings,  "  y  "  should  be  smaller  than  -  by  as 
great  an  amount  as  other  conditions  will  permit. 


CHAPTER  VII. 

MULTIPLE-CIRCUIT,  MULTIPLE- WOUND,  MULTIPOLAR  DRUMS. 

THE  next  windings  to  be  considered  are  multiple-circuit,  multiple-wound,  multipolar  drums. 

The  following  rules  control  these  windings :  — 

The  number  of  conductors,  (7,  must  be  an  even  number.  The  pitches  must  be  odd.  If  y  =  front- 
end  pitch,  then  —  (y  —  2m)  =  back-end  pitch,  where  m  =  number  of  windings  (double,  triple,  quadruple, 
etc.). 

These  "wi"  windings  may  form  one  re-entrant  winding,  "TO"  independent  re-entrant  windings,  or  a 
number  of  re-entrant  windings  equal  to  some  factor  of  "  m,"  each  of  which  re-entrant  windings  is  composed 
of  two  or  more  components. 

To  determine  the  proper  number  of  conductors  for  any  of  the  above  cases,  the  following  rule  should 
be  observed  :  — 

If  "•  m "  equals  the  number  of  windings,  and  "  C "  equals  the  number  of  face  conductors,  then  the  number 

r« 
of  independently  re-entrant  winding*  will  be  equal  to  the  greatest  common  factor  of  —  and  m. 

Fur  instance,  if  a  quadruple  winding  has  28  conductors,  then  the  greatest  common  factor  of  (wi  =  4) 

(C    28         \ 
and  f—  =  ^-=14)  is  2,  and  the  quadruple  winding  will  consist  of  two  independent  double  windings,  each  of 

the  two  being  re-entrant.     This  may  be  represented  symbolically  as  ©  ©• 

(G    24 
—  =—=12)  and  («i  =  4)   is  4,  and  the  quadruple 

winding  will  be  made  up  of  four  independent  single  windings.     This  may  be  represented  symbolically 

as  O  O  O  O- 

I G    ^6        \ 
If  (7=26  and  ?n  =  4,  the  greatest  common  factor  of  (—=^-  =  13)  and  (»i  =  4)  is  1,  and  the   quadruple 

\m         J&  / 

winding  will  consist  of  one  singly  re-entrant  quadruple  winding.     This  may  be  represented  symbolically 

The  above  rule  applies  to  any  winding  (double,  triple,  quadruple,  etc.). 

It  is  interesting  to  note  that,  for  "multiple-«V««'<"  windings,  the  rule  for  the  number  of  multiple  wind- 
ings is  independent  of  the  number  of  poles  and  of  the  pitch. 

The  number  of  conductors,  "(7,"  the  average  pitch,  "y,"  and  the  number  of  poles,  "n,"  should  be 
so  chosen  that  n  x  y  shall  be  somewhere  nearly  equal  to  <7,  being  preferably  a  little  smaller  than  (7. 


77 


78 


AEMATURE   WINDINGS   OF  ELECTHIC  MACHINES. 


.  vn. 


Figure  37  which,  like  Figs.  34  and  35,  has  six  poles  and  fifty  conductors, 
is  a  singly  re-entrant  triple  winding.  (7=50;  m=3.  Greatest  common 

factor  of  —  and  m  is  1.     Therefore,  by  the  preceding  rule,  the  result  is  one 

singly  re-entrant  triple   winding.     The  winding  may  be  represented  sym- 
bolically as  (QQ)  . 

C    50 

The  average  pitch  should  be  a  little  less  than  —  = —  =  8.33,  and  the  for- 

n      b 

ward  and  backward  pitches  must  differ  by  (2m  =6).     Therefore  the  front 
end  pitch  is  taken  #  =  11,  and  the  back-end  pitch  y=  —  5. 

In  the  given  position,  conductors  49  and  4  are  short-circuited  at  a  nega- 
tive brush,  and  12  and  7  at  a  positive  brush.  The  circuits  through  the 
armature  are,  — 


27-32 1 

oq   04. I 

**tf^~*JTI^^ 

31-36-25-30  J 


SIX  CIRCUIT,  TRIPLE  WINDING. 


N 


Fig.  38 
FOUR  CIRCUIT,  QUADRUPLE  WINDING. 


U11AP.   Vll.] 


Ml   LT1PLE-C1RCU1T,  MULTIPLE-WOUND,  MULT1POLAK   DRUMS. 


81 


Figure  38  is  a  four-circuit,  doubly  re-entrant  quadruple  winding  in  which 

C 
w  =  4,  (7=44,  and  TO  =  4.     The  greatest  common  factor  of  -  and  "m,"  i.e.,  of 

m 

22  and  4,  is  2;  therefore  there  are  two  independent,  singly  re-entrant, 
double  windings.  The  winding  may  be  represented  symbolically  by©©. 
These  two  windings  are  represented  on  the  diagram  by  full  and  dotted  lines. 
The  front-end  pitch  has  been  taken  13,  and  the  back-end  pitch  —5,  the 
difference  being  necessarily  2  TO  =  8.  Inspection  will  show  that  the  two 
windings  are,  — 

1_14_  9-22-17-30-25-38-33-2-41-10-5-18-13-26-21-34-29-42-37-6-1 
and 

3-16-11-24-19-32-27-40-35-4^43-12-7-20-15-28-23-36-31^14-39-8-3 

In  the  given  position,  9-14  and  31-36  are  short-circuited  at  the  positive 
brushes.     The  circuits  through  the  armature  are,  — 


4^3-12-  7 

41-  2-33-38 
39-44— 

37^2- 
35-4i 


26-21-34-29 


The  extreme  irregularity  exhibited  in  the  diagrams  and  tables  of  the 
multiple  windings  is  due  to  the  necessarily  small  numbers  of  conductors 
chosen.  With  the  magnitudes  taken  in  practical  work,  everything  will  be 
sufficiently  regular. 


.  i^-^  ~=»-4 

,>"   Of  TH1     •  v^v 


82 


ARMATURE   WINDINGS   OF   ELECTRIC   MACHINES. 


[CHAP.  vn. 


Figure    39  is  the  same    quadruple   winding   as   Fig.  38,   except   that   the   pitches   are   taken    15   and 

-7  instead   of   13   and  —5.       This   was  drawn  to  emphasize  the  fact  that  there  is  nothing    absolute  in 

the    choice    of   the  pitch    in   these  multiple    circuit    armatures,    except    that  in  the  case  of   the   multiple 

windings,  the   numerical   differences   between   the  forward  and  backward  pitches  must    be    equal    to    2  m, 

where  "»w"   is   the   number  of   windings.      As   before  stated,  the   average   pitch  should   not  differ    much 

from  — ,  and  should  be  somewhat  less,  rather  than  greater. 

Figure  38,  which  partakes  in  a  small  degree  of  the  nature  of  the  short  chord  windings  (as  compared 
with  Fig.  39),  has  a  very  much  larger  percentage  of  the  conductors  subjected  to  counter-induction  than 
would  be  the  case  in  actual  practice  with  large  numbers  of  conductors. 

For  instance,  the  average  pitch  might  often  be  represented  by  some  such  number  as  75.  If  it  were 
to  be  a  quadruple  winding,  the  two  pitches  should  differ  by  2  m  or  8.  Therefore  the  forward  pitch 
would  be  taken  79,  and  the  backward  pitch  —71,  so  that  the  order  of  the  winding  would  lie  1-80-9-88, 
etc.,  whereas  in  the  case  of  small  numbers  of  conductors,  such  as  in  Fig.  38,  the  order  of  the  winding 
was  1—14—9—22-17-30,  etc.  It  will  be  evident  that  the  distinction  between  these  two  cases  is,  that  with 
the  larger  number  of  conductors  there  are  many  forward  and  backward  steps  before  the  original  loop 
is  crossed,  thus  :  — 


But  in  the  case  of  the  small  number  of  conductors  the  loop  is  crossed  almost  at  once,  thus :  - 


In  other  words,  with  multiple  windings  and  small  numbers  of  conductors,  the  numerical  differences 
between  the  forward  and  backward  pitches  is  a  large  percentage  of  the  average  pitch,  whereas  with  the 
large  numbers  of  conductors  used  in  practice,  it  is  a  very  small  percentage  of  the  average  pitch. 

The  fact  that  irregularities  are  much  exaggerated  by  the  necessary  choice  of  rather  small  numbers 
of  conductors  should  be  borne  in  mind  in  the  study  of  these  diagrams,  particularly  those  of  multiple 
windings. 

If,  instead  of  the  quadruple  windings  consisting  of  two  independent  doubly  re-entrant  windings  of 
Figs.  38  and  39,  one  singly  re-entrant  quadruple  winding  is  desired,  a  number  of  conductors  must  be 


u — 


N  * 

Fig.  39 
FOUR  CIRCUIT,  QUADRUPLE  WINDING. 


N 


N 


Fig.  40 
SIX  CIRCUIT,  DOUBLE  WINDING. 


CHAP.     VII.] 


MULTIPLE-CIRCUIT,   MULTIPLE- WO  UNO,   MULTIPOLAR   DRUMS. 


85 


C  0 

chosen  such  that  —  and  "r»"  (4)  shall  be  mutually  prime.     Take  (7=42.     Then  —=21,  and  m  =  4,  which 

are  mutually  prime.     If  the  forward   pitch  is  taken  y  =  1'3,   and  the  backward  pitch   y——5,  the  winding 
will  be,  — 

l_14_9_22-17^30-25--38--33-4-41-12-7-20-15-28-23-36-31-2^39-10-5-18-13-2e 
_21^34-29-42-37-8-3-16-ll-24-19-52-27-10-35-6-l 

This  would  be  represented  symbolically  as  (Soo).  w-\  would  be  a  singly  re-entrant  quadruple  winding. 

Q 

If  four  entirely  independent  windings  are  desired,  —   and  "  m  "  must  have  4  for  their  greatest  common 

^ 

factor.      Taking  (7=40,  and  making  the  front  and  back  pitches  respectively  «/=13  and  y=—5,  the  wind- 
big  would  be,  — 

1_14_  9-22-1 7-30-25-58-33-  6-1 

3-16-U-24-19-32-27-40-35-  8-3 

5-18-13-26-21^34-29-  2-37-10-5 

7-20-15-28-23-36-51-  4-39-12-7 


This  could  be  represented  symbolically  as  Q  O  O  O >  IU1(1  would  be  a  quadruply  re-entrant,  quadruple 
winding. 

In   Fig.  40  is   shown   a  six-circuit,   sirfgly    re-entrant,    double   winding.      (7=50,    w  =  6,    m  =  2.      The 

Q 
greatest  common  factor  of  —  and  "  m  "  being  1,  the  winding  is  singly  re-entrant,  and  may  be  represented 

a 

symbolically  as  ©. 

The  forward  pitch  is  y  =  9,  and  the  backward  pitch  is  y=  —  5. 

In  the  given  position,  conductors  49-4,  7-12,  and  15-20  are  short-circuited.      The   circuits   through 
the  armature  are,  — 


8-  I 
6 


1-10-  5/ 


45-50-41-46  1 
47_  2-13-48  i 

24-19-28-23  1 
22-17-26-21  J 


13-18-  9-14 


40-55-44-39  1 
38-33-42-37  1 

29-34-25-30  1 
31-36-27^32  1 


TJIIVBESITY 


CHAPTER   VIII. 

TWO-CIRCUIT,  SINGLE- WOUND,  DRUM  ARMATURES. 

THE  "  two-circuit "  windings  now  to  be  considered  are  distinguished  by  the  fact  that  the  pitch  is  always 
forward,  instead  of  alternately  forward  and  backward,  as  in  the  "multiple-circuit"  windings,  just  described. 

The  sequence  of  connections  leads  the  winding  from  a  certain  bar  opposite  one  pole  piece  to  a  bar  similarly 
situated  opposite  the  next  pole  piece,  and  so  on,  so  that  as  many  bars  as  pole  pieces  are  passed  through  before 
another  bar  in  the  original  field  is  reached.  Such  progression  around  the  armature  is  continued  until  all  the 
bars  are  connected  in,  and  the  winding  returns  on  itself. 

Two-circuit,  drum  windings,  like  the  two-circuit,  gramme-ring  windings,  have  for  a  given  voltage 
the  fraction  -  as  many  conductors  as  multiple-circuit  windings,  with  the  attendant  advantages,  stated  for  the 

rH\i 

two-circuit,  gramme-ring  windings.  The  advantages,  that  the  circuits  from  brush  to  brush  consist  of 
conductors  influenced  by  all  the  poles,  are  —  when  there  is  but  one  turn  in  each  coil  —  the  same  as  in  the  two- 
circuit,  short-connection  ring  winding.  When  there  are  several  turns  in  the  coil,  the  advantages  are  siibject 
to  the  same  reservations  as  in  the  two-circuit,  long-connection,  ring  winding.  The  advantages,  due  to  such 
arrangements  of  the  conductors,  have  been  confined  to  machines  of  small  electrical  output.  In  machines  of 
large  electrical  output,  in  which  there  are  a  number  of  sets  of  brushes  of  the  same  sign  (otherwise  the  cost 
of  the  commutator  is  excessive),  the  advantages  possible  from  equal  currents  in  the  circuits  have  been  over- 
balanced by  the  increased  sparking  due  to  unequal  division  of  the  current  between  the  different  sets  of  brushes 
of  the  same  sign. 

An  examination  of  the  diagrams  will  show  that  in  the  two-circuit  windings  the  drop  in  the  armature, 
likewise  the  armature  reaction,  is  independent  of  any  manner  in  which  the  current  may  be  subdivided 
among  the  different  sets  of  brushes,  but  depends  only  upon  the  sum  of  the  currents  at  all  the  sets  of 
brushes  of  the  same  sign.  There  are,  in  the  two-circuit  windings,  no  features  that  tend  to  cause  the  current 
to  subdivide  equally  between  the  different  sets  of  brushes  of  the  same  sign,  and,  in  consequence,  if  there 
is  any  difference  in  contact  resistance  between  the  different  sets  of  brushes,  or  if  the  brushes  are  not 
set  with  the  proper  lead  with  respect  to  each  other,  there  will  be  an  unequal  division  of  the  current. 

When  there  are  as  many  sets  of  brushes  as  poles,  the  density  at  each  pole  must  be  the  same,  otherwise  the 
position  of  the  different  sets  of  brushes  must  be  shifted  with  respect  to  each  other  to  correspond  to  the  differ- 
ent intensities,  the  same  as  in  the  multiple-circuit  windings. 

In  practice  it  has  been  found  difficult  to  prevent  the  shifting  of  the  current  from  one  set  of  brushes  to 
another.  The  possible  excess  of  current  at  any  one  set  of  brushes  increases  with  the  number  of  sets;  likewise 
the  possibility  of  excessive  sparking.  For  this  reason  the  statement  has  been  sometimes  made  that  the 
disadvantages  of  the  two-circuit  windings  increase  with  the  number  of  poles. 

87 


88  ARMATURE    WINDINGS   OF   ELECTRIC   MACHINES.  [CHAP.  vm. 

From  the  above,  it  may  be  concluded  that  any  change  of  the  armature  with  respect  to  the  poles 
will  in  the  case  of  two-circuit  windings  be  accompanied  by  shifting  of  the  current  between  the  different  sets 
of  brushes;  therefore  to  maintain  a  proper  subdivision  of  the  current  the  armature  must  be  maintained  in  one 
position,  with  respect  to  the  poles,  and  with  exactness,  since  there  is  no  counter  action  in  the  armature 
to  prevent  the  unequal  division  of  the  current. 

In  the  case  of  multiple-circuit  windings,  it  will  be  noted  that  the  drop  in  any  circuit,  likewise 
the  armature  reaction  in  the  field  in  which  the  current  is  generated,  tends  to  prevent  the  excessive 
flow  of  current  from  the  corresponding  set  of  brushes.  On  account  of  these  features,  together  with  the  con- 
sideration that  when  there  are  as  many  brushes  as  poles  the  two-circuit  armatures  require  the  same  nicety  of 
adjustment  with  respect  to  the  poles  as  the  multiple-circuit  windings,  the  multiple-circuit  windings  are 
generally  preferable,  even  when  the  additional  cost  is  taken  into  consideration. 


Denoting  the  number  of  face  conductors  by  " (7,"  the  number  of  poles  by  " n"  and  the  average  pitch  by 
uy,"  the  formula  controlling  the  two-circuit,  single-wound,  multipolar  drum,  is, — 

C=ny±2. 

It  is  preferable  to  have  the  pitch  "y  "  the  same  at  the  two  ends,  because  the  two  sets  of  end  connections 
will  then  be  of  the  same  length,  but  the  choice  of  the  number  of  conductors  "C"'  for  any  particular  case  is 
less  restricted  (when  the  number  of  poles  is  greater  than  four)  if  the  front  and  back  pitches  are  permitted  to 
differ  by  2.  Each  pitch,  must,  moreover,  be  an  odd  number,  as,  in  order  that  the  winding  may  pass  through 
all  the  conductors  before  returning  upon  itself,  it  must  pass  alternately  through  odd  and  even  numbered  con- 
ductors. Also  when,  as  is  usually  the  case,  the  bars  occupy  two  layers,  it  is  necessary  to  connect  from  a 
conductor  of  the  upper  to  one  of  the  lower  layer  so  as  to  obviate  interference  in  the  positions  of  the  spiral  end 
connections.  Where  different  pitches  are  used  at  the  front  and  back  ends,  each  being  odd,  the  average  "  y  " 
appearing  in  the  formula  will  be  even. 


In   Fig.  41   is   given   a   two-circuit,    single  winding   for   a   four-pole    drum.      The    pitch    is    #=!'  at. 
both  ends. 

=  34  or  38. 


Thirty-four  conductors  were  taken.  If  it  is  necessary  to  have  thirty-four  conductors,  it  would  be  better 
to  take  the  average  "y"  equal  to  eight,  and  then  to  use  ^  =  9  at  one  end  and  y  =  l  at  the  other.  It  is  thus 
possible  to  shorten  the  end  connections  at  the  end  at  which  the  shorter  pitch  is  used,  and  thus  avoid  using  an 
unnecessary  amount  of  copper.  This  will  also  make  the  armature  resistance  less,  and  will  give  more  room  for 
the  end  connections. 


Fig.  41, 
TWO  CIRCUIT,  SINGLE  WINDING. 


Fig.  42 
TWO  CIRCUIT,  SINGLE  WINDING, 


CHAP,  viii.]  TWO-CIRCUIT,    SINGLE-WOUND,   DRUM   ARMATURES.  91 

In  Fig.  42  this  has  been  done,  the  front-end  pitch  being  y  =  3  as  before,  but  the  back-end  pitch  being 
y  =  7.     The  average  pitch  is  y  =  %- 

C'=H±2  =  4x8±2  =  30  or  34. 


Thirty-four  conductors  have  been  taken. 

If  thirty-eight  conductors  should  be  preferable  to  thirty-four,  then  the  best  arrangement  would  be  to 
use  i/  =  9  at  both  ends. 

(7=wy±2  =  4x9±2  =  34or  38. 

This  case  has  not  been  drawn,  but  it  would  be  the  proper  method  for  thirty-eight  conductors,  as  the  only 
other  way  would  be  to  have  a  front-end  pitch  ?/  =  ll  and  a  back-end  pitch  #  =  9,  giving  an  average  pitch  y  =  10. 

C  =  n^±2  =  4xlO±2  =  38or  42. 

This  last  choice,  i.e.  pitches  of  0  and  11,  would  be  undesirable,  as  the  connections  at  the  end  with  a  pitch 
of  11  would  be  unnecessarily  long.  Therefore,  as  a  general  rule,  the  pitch  should  be  chosen  a  little  less  than 

-,  and  when  this  would  result  in  an  even  pitch,  the  pitch  at  one  end  may  be  made  O  +  l)  and  at  the  other 

a 

end  (</  —  1).     Of  course,  the  advantage  of  having  both  sets  of  end  connections  exactly  equal  might  offset  the 

small  saving  in  material.     This  would  have  to  be  determined  for  the  case  in  hand.     Often,  however,  even 

where  the  same  pitch  is  used  at  both  ends,  other  considerations  make  it  necessary  to  use  two  differently 

proportioned  sets  of  connecting  strips. 

This  matter  of  the  possibility  of  using  two  different  pitches,  so  that  the  "y"  of  the  equation  C=ny±2 
may  be  any  integer,  odd  or  even,  is  not  so  very  important  in  the  case  of  four-pole  armatures,  as  it  does  not 
increase  the  range  of  choice  of  conductors.  But  for  six,  eight,  and  higher  numbers  of  poles  the  introduction 
of  even  integers  for  "#"  gives  many  more  possible  numbers  of  conductors  than  if  it  were  necessary  to  be 
confined  to  odd  integers. 

Thus,  for  the  case  of  six-pole  windings,  the  formula  C  =  rty±2  becomes  <7=6*/±2.  If  "y"  is  put  succes- 
sively equal  to  10,  11,  12,  13,  14,  and  15,  the  possible  numbers  of  bars  will  become  as  follows:  — 

y  =  10  (7=GO±2=58or62 

y  =  \\  f=  66  ±2  =  64  or  68 

y  =  12  (7=  72  ±2  =  70  or  74 

y  =  18  (7=  78  ±2  =  76  or  80 

y  =  14  (7=84  ±2  =  82  or  86 

»/  =  15  <?=90±2  =  88or  92. 

Thus  it  may  be  seen  that  if  it  were  only  permissible  to  use  odd  integers  for  "  y"  the  possible  conductors 
for  this  range  would  be  limited  to  64,  68,  76,  80,  88,  and  92  ;  but  by  using  unequal  pitches  at  the  two  ends,  the 
average  "  //  "  becomes  even,  and  the  possible  numbers  of  conductors  to  which  the  choice  is  limited  is  doubled. 
It  is  very  important  that  this  point  should  be  borne  in  mind,  as  the  rule  often  used  for  four-pole  machines  that 
C  must  equal  number  of  poles  times  an  odd  number,  plus  or  minus  two,  is  sometimes  mistakenly  extended 
to  larger  numbers  of  poles,  and  a  number  of  conductors  is  chosen  either  larger  or  smaller  than  is  desired  ; 
whereas,  if  different  pitches  at  the  two  ends  had  been  used,  a  much  more  suitable  choice  might  have  been  made. 


92  ARMATURE    WINDINGS   OF  ELECTRIC   MACHINES.  [CJIAI-.  vin. 

Another  limiting  consideration  is,  that  the  numbers  of  conductors  jjerjslot  is  governed  largely  by  the 
capacity  and  voltage  of  the  machine,  so  that  sometimes  two,  sometimes  four,  and  in  exceptional  cases  even  six 
or  eight,  bars  might  be  desired  per  slot,  therefore,  the  total  number  of  conductors  "(7"  must  be  a  multiple  of 
2,  4,  6,  or  8,  as  the  case  may  be.  If,  in  the  case  of  a  six-pole  armature,  only  two  conductors  per  slot  are  desired, 
the  pitch  may  be  either  odd  or  even;  but  it  will  be  found  that  where  four  conductors  per  slot  are  wanted,  and 
where,  therefore,  "  C"  must  be  a  multiple  of  4,  that  only  the  numbers  of  conductors  obtained  by  making  "#" 
an  odd  integer  meet  the  requirement.  And  if  six  conductors  per  slot  should  be  wanted  (and  it  seldom  would 
be,  because  the  mechanical  fitting  of  the  connections  would  be  so  troublesome),  neither  the  use  of  an  odd  nor 
of  an  even  integer  would  (in  the  case  of  a  six-pole  armature)  give  a  possible  number  for  "  (7." 

In  the  following  illustrative  diagrams  it  will  not  be  necessary  to  take  pains  to  show  how  many  conductors 
there  are  per  slot.  They  will  be  drawn  with  the  conductors  spaced  at  equal  intervals,  and  one,  two,  four,  or 
more,  as  desired,  may  be  supposed  to  be  brought  together  iii  a  slot. 


In  Fig.  43  is  given  a  diagram  for  a  six-pole,  two-circuit,  single-wound,  drum  armature.    The  pitch  is  v/=ll 
at  both  ends. 


Sixty-eight  conductors  were  taken,  and  they  could  be  arranged  one,  two,  or  four  per  slot,  as  other 
conditions  might  determine. 

In  the  position  shown,  the  positive  brush  short-circuits  the  group  of  conductors  5-62-51-40-29-18,  all  in 
series.  The  circuits  through  the  armature  are,  — 

6-17-28-39-50-61-  4-15-26-37-48-59-  2-13-24-35-46-57-68-11-22-3:5-41-55-66-  9-20-31-42-53-64-7  \ 


63-52-41-30-19-  8-65-54-43-32-21-10-67-50-45-34-23-12-  1-58-47-30-25-14-  3-GO-49-38-27-10— 

An  examination  of  the  preceding  table  will  show  that  immediately  sequential  conductors,  such  as  G  and  7, 
have  between  them,  at  recurring  periods,  the  full  difference  of  potential  of  the  winding.  But  altt'ninti-lii 
sequential  pairs  of  conductors,  as  6  and  4,  or  63  and  65,  have  between  them  only  the  difference  of  potential  of 
"  n  "  bars. 

For  the  above  analysis,  only  the  two  full-lined  brushes  were  supposed  to  be  in  service.  If,  however,  the 
four  brushes  shown  by  the  dotted  lines  were  added,  the  short-circuited  bars  would  consist  of  groups  of  two 
each,  in  series  between  different  brushes  of  like  sign.  In  the  given  position,  these  groups  would  be  5-62, 
51-40,  and  29-18  at  the  positive  brushes,  and  63-52,  41-30,  and  17-6  at  the  negative  brushes.  The  circuits 
through  the  armature  would  be  the  same,  with  the  exception  that  the  bars  short-circuited  by  the  negative 
brushes  would  now  disappear  from  the  list.  These  six  conductors,  6,  17,  63,  52,  41,  30,  have  been  underlined  in 
the  table,  and  are  marked  on  the  diagram  by  small  circles. 


Fig.  43 
TWO  CIRCUIT,  SINGLE  WINDING, 


N 


. 


43 


41 


+X-, 


39 


H-/ 


37 


.36 


29  4 


281 


21 


22) 


23V 


25V 


Fig.  44 
TWO  CIRCUIT,  SINGLE  WINDING. 


CHAI-.  viii.]  TWO-CIRCUIT,    SINGLE-WOUND,   DKUM    ARMATURES.  95 


In  Fig.  44  is  given  a  diagram  for  a  two-circuit,  six-pole 
armature.  The  back-end  pitch  is  «/  =  7,  and  the  front-end 
pitch  is  y  =  9.  Therefore  the  average  pitch  is  #  =  8. 

<7=w#±2  =  6x8±2  =  46  or  50. 

Fifty  conductors  are  taken.  As  in  the  preceding  dia- 
gram, only  the  six  conductors  without  arrow-heads  are 
short-circuited  when  the  two  full-line  brushes  alone  are 
active.  But  when  all  six  brushes  bear  on  the  commutator, 
the  conductors  designated  by  small  circles  are  also  short- 
circuited. 


0V  TH*        >{•- 

TJFIVEESITY; 


96  ARMATURE    WINDINGS   OF    ELECTRIC    MACHINES.  [CHAI-.  vm. 


TWO-CIRCUIT  WINDINGS   WITH  .CROSS-CONNECTED  COMMUTATORS. 

Figures  45,  46,  47,  and  48  are  illustrative  of  a  class  of  two-circuit  windings  that  possess 
the  distinctive  feature  that  the  number  of  coils  may  bear  a  relation  to  the  number  of  poles 
not  possible  with  the  other  two-circuit  windings  described.  An  examination  of  the  dia- 
grams will  show  that  the  different  coils  of  a  winding  may  be  subdivided  in  groups,  each 
group  having  either  as  many  coils  as  there  are  pairs  of  poles,  or  half  as  many,  these 
different  groups  being  connected  in  series  by  a  cross-connected  commutator. 

Figure  45  is  an  example  of  this  class.  As  will  be  seen,  it  consists  of  an  eight-pole 
drum  armature,  with  fifty-six  conductors  connected  up  as  a  two-circuit,  single  winding. 

The  underlying  principle  is  best  understood  by  noting  one  "  element "  of  the  winding, 
such  as  the  eight  polar  conductors  drawn  with  very  heavy  lines.  It  starts  from  a  certain 
commutator  segment,  and  after  proceeding  under  each  of  the  eight  pole  pieces,  it  returns 
to  the  adjacent  segment.  It  should  be  further  observed  that,  unlike  the  heretofore 
described  two-circuit  drum  armatures,  the  conductors  of  this  element  are  separated  fnnn 
each  other  by  an  angular  distance  equal  exactly  to  £$-a  =  45°,  instead  of,  as  in  the  ordinary 
two-circuit  drum  windings,  being  separated  by  an  angular  distance  a  little  greater  or  less 

than  this. 

(7=56,  w=8,  y  (the  "pitch ")  =  s/  =  7. 

It  should  be  particularly  noted  that,  with  this  winding,  a  number  of  conductors  is  used 
which  is  an  exact  multiple  of  the  number  of  poles.  This,  of  course,  is  not  possible  with 
the  ordinary  two-circuit  drum  windings,  which  are  controlled  by  the  formula  - 

C=ny  ±2. 

As  will  be  seen  from  the  diagram,  this  winding  requires  cross-connection  of  the  com- 
mutator, but  in  many  machines  this  disadvantage  might  be  offset  by  the  fact  that,  owing 
to  the  symmetrical  arrangement  of  the  conductors  with  reference  to  the  pole  pieces,  the 
objectionable  "  selective  commutation  "  of  the  ordinary  type  would  probably  be  avoided. 

C    56 
To  return  to  a  study  of  the  diagram,  it  will  be  seen  that  there  are  —=  —  =  7  sets  of 

ft  O 

"elements"  exactly  the  same  as  that  above  described,  except  that  each  is  located  at  an 
angular  distance  of  &%&  from  the  preceding  one.  To  facilitate  comprehension  of  the 
diagram,  these  seven  "  elements  "  have  been  drawn  in  with  different  styles  of  lines,  and 
are  readily  distinguishable. 

It  is  therefore  obvious  that,  if  it  were  not  for  the  commutator  cross-connections,  the 
winding  would  consist  of  seven  sets  of  eight  conductors  each,  and  that  each  such  set  has 
its  two  terminals  at  a  pair  of  adjacent  segments.  These  individual  coils  are  put  in  the 
proper  series  relation  between  brushes  by  the  commutator  cross-connection.  The 
resultant  design  is  perfectly  symmetrical. 


/\ 


X 


,\ 


\  ^  \ 
\\ } 


J    / 


\  ^ 

\     .S 


s* 


y 


\ 


i — 


Fig.  45 


..  .         ...„ - 


Fig.  46 


CHAP,  via.]  TWO-CIRCUIT,   SINGLE-WOUND,   DRUM   ARMATURES.  99 


Figure  46  differs  only  in  having  forty-eight  conductors, 
with  the  necessary  consequence  that,  the  pitch  being  even 
(4^  =  6),  it  has  to  be  different  at  the  front  and  back.  It  is 
seven  at  the  commutator  end,  and  five  at  the  other  end. 
This  slight  irregularity  makes  the  wording  of  the  description 
of  Fig.  45  not  absolutely  applicable  to  this  diagram,  the  chief 
difference  being  that,  although  every  pair  of  successive  con- 
ductors are  exactly  similarly  located  with  respect  to  a  pair 
of  poles  as  every  other  pair,  the  same  cannot  be  said  of  every 
individual  conductor  of  an  element,  the  distance  between 
them  being  successively  greater  and  less  than 


.100  ARMATURE  WINDINGS  OF  ELECTRIC   MACHINES.  [CHAP.  vm. 


Figure  47  represents  a  two-circuit  single-winding,  identi- 
cal with  Fig.  45,  except  that  the  connecting  leads  at  the 
front  end  are  twice  as  long. 

This  is  used  in  some  "  form  "  windings,  where  the  two 
ends  of  a  coil  are  brought  out  in  front  at  a  point  half-way 
between  the  two  slots  holding  the  wires  of  a  coil.  The  long 
front  connections  would  never  be  used  in  bar  windings, 
where  each  face  conductor  of  the  diagram  represents  only 
one  conductor,  for  it  would  be  a  waste  of  copper.  Short 
leads  such  as  those  of  Fig.  45  would,  for  such  bar  windings, 
always  be  used. 

An  "  element "  of  the  winding  may  be  readily  seen  from 
the  heavy  lining  in  the  diagram. 

Windings  of  same  type  as  Fig.  47  could  be  made  corre- 
sponding to  Fig.  46,  as  well  as  to  Fig.  45.  In  fact,  the 
underlying  principle  of  this  winding  is  identical  with  that  of 
the  type  illustrated  by  Figs.  45  and  46. 


UZTIVEP.SITY 


Fig.  48 


CHAP,  viii.]  TWO-CIRCUIT,   SINGLE-WOUND,   DRUM   ARMATURES.  103 


Figure  48  represents  a  two-circuit  single  winding  for  an 
eight-pole  machine,  in  which  four  conductors  constitute  an 
element.  The  number  of  conductors  is  here  taken  to  be 
fifty-two.  There  are  therefore  5j2-=13  elements.  It  is  a 
condition  of  this  winding  that  the  number  of  elements  must 
be  an  odd  number.  From  this  it  follows  that  the  total 
number  of  conductors  cannot  be  a  multiple  of  the  number 
of  poles. 

It  serves,  therefore,  for  numbers  of  conductors  with 
which  the  previously  described  winding  (where  C  is  a 
multiple  of  ri)  could  not  be  used.  It  probably,  however, 
would  not  be  so  well  balanced  as  in  the  case  where  C  is  a 
multiple  of  n.  The  commutator  requires  cross-connecting, 
as  shown  in  the  diagram.  The  cross-connections  at  the  front 
end  are  of  twice  the  usual  length. 


104  AKMATUEE    WINDINGS   OF   ELECTRIC   MACHINES.  [CHAP.  vm. 


WENSTROM  TWO-CIRCUIT,  WIRE-WOUND  ARMATURE. 

Figure  49  represents  a  winding  devised  by  Wenstrom  to 
lessen  the  depth  of  the  end  windings  of  wire  wound  arma- 
tures. 

The  particular  case  represented  by  the  diagram  had 
thirty-five  lozenge-shaped  slots,  each  containing  four  con- 
ductors. For  the  sake  of  clearness  only  the  connections  of 
the  wires  between  two  adjacent  commutator  segments  are 
shown,  and  no  difficulty  will  be  found  in  completing  the 
winding,  by  continuing  on  through  the  remaining  segments. 

This  method  is,  of  course,  only  suitable  for  wire-wound 
armatures  and  like  most  such  wire  windings,  it  is  difficult  to 
repair. 

It  is  to  be  noted  that  these  armatures,  which  have  been 
quite  extensively  used,  were  completely  ironclad,  there  being 
no  slot  opening. 


Fig.  49 


Fig.  5O 
TWO  CIRCUIT,  SINGLE  WINDING. 


CHAPTER   IX. 

INTERPOLATED   COMMUTATOR   SEGMENTS. 

IN  Fig.  50  is  given  a  two-circuit  single  winding.  w  =  6,  y  =  13,  C=ny±2  =  6  x!3±2  =  76  or  80.  Eighty 
conductors  have  been  taken.  This  would  naturally  give  forty  commutator  segments.  Suppose  speed,  strength 
of  field,  and  active  length  of  conductors  to  be  of  such  magnitudes  as  to  generate  one  volt  per  conductor. 

OQ 19 

Noting  that,  as  shown  in  the  figure,  twelve  conductors  arc  short-circuited,  there  will  be  — - — -=34  active 

Jt 

conductors  in  series  between  brushes-     Therefore  the  total  E.M.F.  will  be  34  volts.     There  would  be  (before 

-in     c 
interpolating)       ~    =5.67  segments  between  every  two  neutral  points  of  the  commutator.     Therefore  there 

I! 

would  be  =(i  volts  between  every  two  adjacent  segments. 

5 .  o  7 

Suppose  this  to  be  higher  than  is  desired.  It  might  then  be  proposed  to  double  the  number  of  segments 
by  the  method  of  cross-connecting  shown  in  Fig.  50.  This  will  increase  the  number  of  segments  to  eighty. 
Following  the  circuit  through  from  the  negative  to  the  positive  brush,  the  conductors  have  been  labeled  1  volt, 
-  volts,  3  volts,  etc.,  adding  one  volt  for  each  conductor.  Taking  the  potential  of  the  negative  brush  as  zero, 
this  gives  the  potential  of  each  conductor.  Following  down  from  each  conductor  to  its  attached  segments, 
they  have  been  numbered  in  a  corresponding  manner;  thus  the  four  segments  connected  to  the  two  bars  at 
20  volts  potential  have  been  marked  20,  etc. 

An  examination  of  the  figure  will  now  make  it  apparent  that  proceeding  from  the  neutral  points  (at  zero 
potential)  the  voltage  increases  alternately  by  two  and  by  four  volts  per  segment,  the  average  being  three 
volts  per  segment.  Therefore,  although  the  average  volts  per  segment  have  been  decreased  to  one-half  of 
what  they  were  for  forty  segments,  half  of  the  segments  have  between  them  only  one-third,  and  the  remainder, 
two-thirds,  of  the  original  volts  per  segment  Therefore,  for  a  six-pole  armature,  the  volts  per  segment  cannot 
be  halved  by  interpolation.  And  in  order  to  reduce  them  to  one-third  throughout,  it  is  not  sufficient  to  cross- 
connect  as  shown  in  the  figure,  but  it  is  necessary  to  triple  the  natural  number  of  segments  and  cross-connect 
every  three  corresponding  segments.  This  would  be  far  from  simple. 

107 


U3UVZKSITY 


108  ARMATURE   WINDINGS  OF  ELECTRIC   MACHINES.  [CHAI-.  ix. 


A  fairly  large  number  of  conductors  was  taken  in  Fig.  50,  in  order  to 
give  a  thorough  explanation  of  the  principles  involved  in  interpolating 
segments.  The  further  study  of  the  subject  can,  however,  be  more  satis- 
factorily carried  on  with  small  numbers  of  conductors. 

In  Fig.  51  is  shown  another  two-circuit,  single  winding,  with  w  =  6,  #  =  7, 
C=  ny  ±  2  =  6  x  7  ±  2  =  40  or  44.  Forty -four  conductors  are  taken.  Without 
interpolation,  twenty-two  segments  would  be  used.  Here  3x22  =  66  seg- 
ments are  used.  This  is  arrived  at  by  connecting  together  every  three 
corresponding  commutator  segments. 

If,  as  in  the  preceding  figure,  only  two  segments  had  been  cross-con- 
nected, the  connections  shown  by  the  full  lines  would  have  sufficed.  Crows- 
connecting  every  three  corresponding  segments  involved  the  addition  of  the 
dotted  line  connections.  This,  as  the  diagram  shows,  doubles  the  total 
number  of  commutator  cross-connections,  and  is  therefore  mechanically 
objectionable. 

But  the  volts  between  bars  are  now  everywhere  equal  instead  of  being 
alternately  F"and  2F"as  in  Fig.  50.  This  may  be  seen  by  an  examination 
of  the  numbers  on  the  conductors  and  segments,  which  have  been  arranged 
according  to  the  conventional  method  described. 

Thus,  proceeding  from  the  segments  under  the  negative  brush,  the 
voltage  would  increase  regularly  by  two  volts  per  segment  up  to  the  positive 
brush,  so  that  whereas,  in  the  former  cases,  the  order  was  2,  4,  8,  10,  14,  16, 
etc.,  it  is  now  2,  4,  6,  8,  10,  12,  14,  16,  etc. 


TWO  CIRCUIT,  SINGLE  WINDING. 


Fig.  52 
TWO  CIRCUIT,  SINGLE  WINDING. 


< 'HAP.  ix.]  INTERPOLATED   COMMUTATOR   SEGMENTS.  Ill 


In  Fig.  52  is  given  the  diagram  of  a  two-circuit,  single- 
wound,  eight-pole  armature  with  forty-two  conductors. 
C=n//±2;  8x5  +  2  =  42.  It  is  given  to  show  that,  with 
even  numbers  of  pairs  of  poles,  the  number  of  commutator 
bars  may  be  doubled  by  interpolation,  and  that  the  result 
will  be  to  halve  the  volts  between  every  two  segments  in- 
stead of  producing  the  unsymmetrical  result  observed  in  the 
case  of  an  odd  number  of  pairs  of  poles. 

An  examination  of  Fig.  52  will  show  that  commutator 
segments  180°  apart  are  cross-connected.  The  scheme  of 
studying  the  relative  potential  of  conductors  and  commu- 
tator segments  is  the  same  as  that  used  in  the  case  of  the 
two  preceding  figures,  and  can  be  followed  through  without 
trouble.  Some  confusion  may  result  from  the  fact  that 
owing  to  the  small  number  of  conductors  taken,  the  length 
of  the  two  circuits  through  the  armature  are  quite  unequal, 
one  path  consisting  of  twelve  conductors,  and  the  other  of 
fourteen.  As  the  positive  neutral  points  where  these  two 
paths  meet  must  be  at  the  same  potential,  all  the  segments  at 
these  positions  have  been  indicated  as  being  at  a  potential 
of  fourteen  volts,  so  that  the  sequence  of  figures  giving  the 
potentials  of  the  segments  is,  in  four  of  the  eight  cases,  0,  4, 
8,  12,  14  ;  increasing  regularly  by  four  volts  until  the  very 
end,  where  the  increase  is  but  two  volts. 

In  the  other  four  cases,  for  the  same  reason,  the  sequence 
is  0,  2,  6,  10,  14,  showing  the  irregularity  at  the  negative 
neutral  points.  .With  the  large  number  of  conductors  used 
in  practice  no  misunderstanding  would  result. 


112  AKMATURE   WINDINGS   OF   ELECTKIC   MACHINES.  [CHAF.  ix. 


With  an  even  number  of  pairs  of  poles  it  is  not  necessary 
to  be  confined  to  using  only  twice  the  natural  number  of 
commutator  segments.  Thus  in  Fig.  53  is  given  the  same 
eight-pole  winding  as  in  Fig.  52,  with  the  exception  that 
eighty-four  segments  are  used  instead  of  forty-two.  The 
natural  number  ol  segments  would  be  twenty-one. 

As  the  conventions  used  in  the  previous  descriptions  are 
followed  in  mapping  out  the  relative  potentials  of  the  various 
parts,  no  further  explanations  will  be  necessary. 


Fig.  53 
T.WO  CIRCUIT,  SINGLE  WINDING. 


CHAPTER   X. 

TWO-CIRCUIT,  MULTIPLE-WOUND,  DRUM   ARMATURES. 

THE  next  class  is  that  of  the  two-circuit,  multiple-wound,  drum  armature. 

The  general  formula  is  :  — 

C=ny  ±-2m, 

where  G  =  number  of  face  conductors, 

n  =  number  of  poles, 
y  =  average  pitch, 
m  —  number  of  windings. 

The  "m"  windings  will  consist  of  a  number  of  independently  re-entrant  windings,  equal  to  the  greatest 
common  factor  of  "y"  and  "MI."  Therefore,  where  it  is  desired  that  the  "TO"  windings  shall  combine  to 
form  one  re-entrant  system,  it  will  be  necessary  that  the  greatest  common  factor  of  "y"  and  "TO"  be  made 
equal  to  1. 

Also,  when  "#"  is  an  even  integer,  the  pitch  must  be  taken  alternately  as  (y  —  1)  and 


In  Fig.  54  is  reproduced  a  winding  described  by  E.  Arnold  ("  Die  Ankerwicklungen  der  Gleichstrom- 
Dynamomaschinen,"  p.  70,  Fig.  80),  and  by  Dr.  Kittler  ("Handbuch  der  Elektrotechnik,"  2d  ed.,  p.  .">:;.">, 
Fig.  403,  5).  It  is  classified  by  them  as  a  four-circuit,  single  winding.  They  show  four  narrow  brushe,s, 
and  point  out  that  the  winding  has  the  peculiarities  that,  in  connecting  up,  the  pitch  is  always  taken  forward, 
and  that  the  short-circuiting  of  a  coil  occurs  between  opposite  brushes  of  like  polarity,  instead  of  entirely  at 
one  brush,  as  is  usually  the  case.  They  give  no  further  instances  of  the  application  of  this  winding,  except 
that  Herr  Arnold  proposes  for  it  the  formula:  — 


Q 

and  adds  that  if  -^  and  "  y  "  have  a  common  factor,  a  singly  re-entrant  winding  is  not  obtained,  several  inde- 
pendently re-entrant  windings  being  the  result.  lie  follows  this  statement  with  a  diagram  having 
(7=28,  n  =  4,  and  y  =  6.  [28  =  4(6  +  1)], 

which  gives  two  independently  re-entrant  windings,  and  shows,  as  before,  four  points  of  commutation. 

Returning  to  a  consideration  of  Fig.  54,  it  may  be  seen  that  at  the  given  position,  conductors  5-12  and 
21-28  are  short  circuited  at  the  negative  brushes,  and  13-20  and  29-4  at  the  positive. 

The  circuits  through  the  armature  are,  — 

3-10-17-24^31-  (r 
30-23-16-  9-  2-27 

14_  7-32-25-18-11 
19-26-  1-  8-15-22 
114 


\32 


\30 


(29 


/2    ' 


28 


w, 


(27 


N 


26 


24 


10 


12 


N 


20/ 


13) 


17 


20, 


Fig.  55 
TWO  CIRCUIT,  DOUBLE  WINDING. 


CHAP,  x.j 


TWO-CIRCUIT,   MULTIPLE-WOUND,   DRUM   ARMATURES. 


117 


Now  in  Fig.  55  will  be  found  the  very  same  winding  as  in  Fig.  54,  with  the  excep- 
tion that  two  wide  brushes  are  shown  instead  of  four  narrow  ones.  Short-circuiting  of 
a  coil  now  necessarily  occurs  at  one  brush,  and  a  study  of  the  winding  shows  that  it  is 
one  of  the  singly  re-entrant  multiple-wound  type,  this  particular  one  being  a  two-circuit, 
singly  re-entrant,  double  winding. 

At  the  position  shown,  conductors  7-14-21-28  are  short-circuited  at  the  negative 
brush,  and  15-22-29-4  at  the  positive.  The  circuits  through  the  armature  are  :  — 

( 


3-10-17-24-31-  G 

30-23-16-  9-  2-27-20-13 


32-25-18-11 

5-12-19-26-  1-  8- 


It  will  be  seen  that,  owing  to  the  very  small  number  of  conductors,  the  winding  is 
extremely  irregular,  but  it  will  not  be  difficult  to  perceive  that  the  nature  of  the  course 
taken  by  the  current  through  the  armature  remains  essentially  unaltered  from  that  of 
Fig.  54,  consisting,  as  there,  of  four  paths  with  an  average  of  six  conductors  in  series  per 
path.  The  current,  however,  enters  the  armature  from  one  wide  brush,  which  always 

/360\° 
spans  more  than  one  segment,  and  departs  from  a  similar  wide  brush  ( )  removed. 

\  n  j 

But  in  the  former  case  (Fig.  54),  it  entered  two  of  the  paths  by  one  narrow  negative 

r360~l° 

brush,  and  the  other  two  by  another,  situated     distant. 

n 

It  appears,  therefore,  conclusive  that  Fig.  54  is  in  all  essential  respects  identical  with 
a  two-circuit,  singly  re-entrant,  double  winding,  but  this  was  probably  not  perceived  by 
the  above-mentioned  authors:  otherwise  they  would  undoubtedly  have  extended  the  prin- 
ciple to  higher  orders  of  multiples  and  other  numbers  of  poles.  An  eight-pole,  two-circuit, 
singly  re-entrant,  triple  winding  (which  would,  of  course,  follow  six  paths  through  the 
conductors  of  the  armature)  would  probably  not  have  been  considered  possible,  their  con- 
ception of  the  winding  apparently  being  that  it  was  a  multiple  winding  with  as  many 
paths  through  the  conductors  of  the  armature  as  the  machine  had  poles.  The  formula 
and  rules  enunciated  in  this  investigation  follow  naturally  from  the  true  conception  of  this 
winding,  whereas  the  formula  and  condition  stated  by  Herr  Arnold  may  be  seen,  by  a  few 
attempts  to  apply  it,  to  be  entirely  inadequate  for  the  purpose  of  obtaining  the  necessary 
data  for  constructing  such  windings. 


OF 

2TI7BRSIT 


118 


ARMATURE   WINDINGS   OF   ELECTRIC   MACHINES. 


[CHAP.  x. 


The  two  preceding  figures  (54  and  55)  were  given  for  the  purpose  of  showing  in  how  far  the  two-circuit, 
multiple  windings  have  been  understood  in  the  past.  The  numbers  of  conductors  were,  however,  entirely 
inadequate  to  fully  illustrate  the  nature  of  the  windings. 

As  this  class  promises  to  have  a  somewhat  wide  application,  it  is  proposed  to  give  a  good  many  examples, 
selecting  for  the  purpose  various  values  of  "(7,"  "»,"  "y"  and  "/«,"  and  briefly  analyzing  each  case  on  the 
basis  of  the  rules  given  on  page  114. 

The  symbolical  representations  heretofore  used  will  be  continued,  thus :  — 


o 


will  represent 

will  represent 

will  represent 

will  represent 

will  represent 

will  represent 

©  ©       will  represent 

O  O  O  O  will  represent 


00 

ooo 


a  singly  re-entrant  single  winding, 

a  singly  re-entrant  double  winding, 

a  doubly  re-entrant  double  winding, 

a  singly  re-entrant  triple  winding, 

a  triply  re-entrant  triple  winding, 

a  singly  re-entrant  quadruple  winding, 

a  doubly  re-entrant  quadruple  winding, 

a  quadruply  re-entrant  quadruple  winding. 


According  to  the  above  nomenclature,  Fig.  40  would  be  a  six-circuit,  singly  re-entrant,  double  winding 
[©]  J  Fig-  37  would  be  a  six-circuit,  singly  re-entrant,  triple  winding  [  (QQ)  ] ;  and  Fig.  38  a  four-circuit, 
doubly  re-entrant,  quadruple  winding  [©©]-  The  use  of  the  middle  expression,  "singly,  doubly,  etc., 
re-entrant,"  is  unavoidable  for  absolute  definiteness,  but  it  will  in  most  cases  be  sufficiently  definite  to  speak, 
for  example,  of  a  "  six -circuit,  triple  winding"  and  a  "two-circuit,  quadruple  winding,"  where  absolute  exact- 
ness would  require  them  to  be  spoken  of  respectively  as  a  "  six-circuit,  singly  re-entrant,  triple  winding  "  and 
a  "two-circuit,  doubly  re-entrant,  quadruple  winding." 


Figure  56  is  a  four-pole,  two-circuit,  singly  re-entrant,  triple  winding.  It  is  represented  symbolically 
thus:  (So).  w  =  4,  and  wi  =  3.  In  order  that  it  should  be  singly  re-entrant,  it  was  necessary  for  the 
greatest  common  factor  of  um"  and  "y"  to  be  1.  Therefore  "«/"  was  taken  equal  to  16. 

C=ny±  2  m  =  4x!6±  2x3  =  58  or  70. 

Seventy  conductors  have  been  taken,  and  "y"  is  alternately  15  and  17,  it  being,  of  course,  impossible 

to  use  16. 

In  the  position  shown,  the  conductors  without  arrowheads  are  short-circuited,  and  the  circuits  through 

the  armature  are :  — 

67-50-35-18-  3-56-41-24 } 


G5-48-33-16-  1-54^39-22 — 
63-46-31-14-69-52-37-20-  5^58-43-26 

10-27^12-59-  4-21-36-53-68-15— 
8-25-40-57-  2-19-34-51-66-13— 
6-23-38-55-70-17-32^9-64-11 


Fig.  56 
TWO  CIRCUIT,  TRIPLE  WINDIN 


IVERSITY 


Fig.  57 
TWO  CIRCUIT,  TRIPLE  WINDING. 


CHAP.   X.] 


TWO-ClilCUIT,   MULTIPLE-WOUND,   DKUM   AKMATUKES. 


121 


Figure  57  is  a  four-pole,  two-circuit,  triply  re-entrant, 
triple  winding.  It  would  be  represented  symbolically  as 
O  O  O-  n  =  4,  and  w  =  3.  In  order  that  it  should  be  triply 
re-entrant,  it  was  necessary  for  the  greatest  common  factor 
of  "ra"  and  "#"  to  be  3.  Therefore  "y"  was  taken  equal 

to  15. 

3  =  54or  66. 


Sixty-six  conductors  have  been  taken.  The  three  inde- 
pendently re-entrant  windings  have  been  shown  by  three 
different  styles  of  lines. 

In  the  position  shown,  the  conductors  without  arrow- 
heads are  short-circuited,  and  the  circuits  through  the 
armature  are  :  — 


63-48-33-18-  3-54-39-24 

61-46-31-16-  1-52-37-22— 
59_44_29-14-65-50-35-20-  5-56-41-26 


10-25-40^55-  4-19-34-49-64-13- 
8-23-38-53-  2-17-32-47-62-11- 
6-21-36-51-66-15-30^15-60-  9- 


It  is  interesting  to  compare  this  winding  and  table  with 
the  preceding,  and  to  notice  how  very  slightly  they  differ. 


122  ARMATURE  WINDINGS  OF  ELECTRIC  MACHINES.  [CHAP.  x. 


Figure  58  is  a  six-pole,  two-circuit,  singly  re-entrant, 
double  winding.  It  would  be  represented  symbolically 
as  ©.  n  =  6,  and  m  =  2. 

In  order  that  it  should  be  singly  re-entrant,  it  was  neces- 
sary for  the  greatest  common  factor  of  "  m  "  and  "  y  "  to  be  1. 
Therefore  "  y  "  was  taken  equal  to  9. 

tf=w#±2m=6x9±2x2=50  or  58. 

Fifty-eight  conductors  have  been  taken. 
In  the  position  shown,  the  circuits  through-  the  armature 
are :  — 

r  57-48-39-30-21-12-  3-52-13-34-25-16 

55-46-37-28-19-10-  1-50-41-32-23-14 

->- 

6-15-24-33-42-51-  2-11-20-29-38-47-56-7 

.    4-13-22^31-40-49-58-  9 


Fig.  58 
TWO  CIRCUIT,  DOUBLE  WINDING. 


Fig.  59 
TWO  CIRCUIT,  DOUBLE  WINDING. 


CHAP,  x.j  T \VO-C11UJUIT,   MULTIPLE-WOUND,   DKUM   AKMATUKES.  125 


Figure  59  is  a  six-pole,  two-circuit,  doubly  re-entrant, 
double  winding,  the  symbolical  representation  being  Q  O- 
n  =  G,  and  m  =  2.  In  order  that  it  should  be  doubly  re- 
entrant, it  was  necessary  for  the  greatest  common  factor  of 
"m"  and  "y"  to  be  2.  Therefore  "y"  was  taken  equal 
to  8. 

G-ny  ±  2  m  =  \i  x  8  ±  2  x  2  =  44  or  52. 

Fifty -two  conductors  have  been  taken,  and  "  y  "  is  alter- 
nately 7  and  9,  it  being,  of  course,  impossible  to  use  «/  =  8. 

In  the  position  shown,  the  conductors  without  arrow- 
heads are  short-circuited,  and  the  circuits  through  the 
armature  are :  — 

I  51-44-35-28-19-12—    


49-42-33-26-17-10-  1^6-37-30-21-14 

6-13-22-29-38-15-  2-  9-18-25-34-41-50-  5 
I    4-11-20-27-36-13-52-  7 


As  frequently  remarked  in  connection  with  other  dia- 
grams having  small  numbers  of  conductors,  the  very  unequal 
lengths  of  the  different  paths  through  the  armature  is 
entirely  caused  by  this  choice  of  a  small  number  of  con- 
ductors, and  would,  to  a  large  extent,  disappear  with  all 
practicable  numbers  of  conductors. 

The  two  independently  re-entrant  windings  are  drawn 
respectively  with  full  and  with  dotted  lines. 


rawO 
I7BRSIT7] 


126 


ARMATURE   WINDINGS   OF   ELECTRIC   MACHINES. 


[CHAP.  x. 


Figure  60  is  a  six -pole,  two-circuit,  triply  re-entrant,  triple 
winding.  It  would  be  represented  symbolically  as  Q  O  O- 
w  =  6,  and  m=3.  In  order  that  it  should  be  triply  re-entrant, 
it  was  necessary  for  the  greatest  common  factor  of  "  m  "  and 
"  y  "  to  be  3.  Therefore  "  y  "  was  taken  equal  to  9. 

C'=ny±2™  =  6x9±2x3=48or  60. 

Sixty  conductors  have  been  taken. 

The  three  independently  re-entrant  windings  have  been 
represented  by  three  different  styles  of  lines. 

In  the  position  shown,  the  circuits  through  the  armature 
are :  — 


59-50^11-32-23-14- 
57-18-39-30-21-12- 


55-46-37-28-19-10-  1-52-43-34-25-16 


6-15-24-33-42-51-60-  9- 
4-13-22-31-40-49-58-  7- 
2-11-20-29-38-47-56-  5- 


Fig.  60 
TWO  CIRCUIT,  TRIPLE  WINDING. 


N 

Fig.  61 
TWO  CIRCUIT,  TRIPLE  WINDING. 


i   IIA1-.   X.] 


TWO-CIRCUIT,   MULTIPLE-WOUND,   DRUM   ARMATURES. 


Figure  61  is  a  six-pole,  two-circuit,  singly  re-entrant, 
triple  winding  It  may  be  symbolically  expressed  as  (QQ)  • 
w  =  6,  and  TO  =3.  In  order  that  it  should  be  singly  re- 
entrant, it  was  necessary  for  the  greatest  common  factor  of 
"wt"  and  "y"  to  be  1.  Therefore  "y"  was  taken  equal  to  8. 

=  6x8±2x3=42or  54. 


Fifty-four  conductors  have  been  taken,  "y"  is  alter- 
nately 7  and  9,  as  it  would,  of  course,  be  impossible  to  let 
y-8. 

In  the  position  shown,  the  circuits  through  the  armature 
are  :  — 


53-46-37-30-21-14 

51_44_35_28-19-12— 
49-42-33-26-17-10-  1-48-39-32-23-16 


8-15-24-31-10-47-  2-9- 
6-13-22-29-38-45^54-7- 
4_1 1-20-27-36-43-52-5- 


-I- 


130 


AKMATURE  WINDINGS  OF  ELECTRIC   MACHINES. 


[CIIAI-.  x. 


Figure  62  is  a  six-pole,  two  circuit,  triply  re-entrant, 
triple  winding.  It  would  be  represented  symbolically  as 
OOO-  w  =  6,  m  =  3.  In  order  that  it  should  be  triply  re- 
entrant, it  was  necessary  for  the  greatest  common  factor  of 
to  be  3.  Therefore  "y"  was  taken  equal 


"y"  and 

to  12. 


•m 


=  66  or  78. 


Seventy  -eight  conductors  have  been  taken,  and  "y"  is 
alternately  11  and  13,  as  it  would  not  be  possible  to  let 


The  three  independently  re  entrant  windings  have  been 
represented  by  three  different  styles  of  lines. 

In  the  position  shown,  the  short-circuited  conductors  are 
those  without  arrow-heads.  The  circuits  through  the  arma- 
ture are  :  — 


75-64-51-40-27-16-  3-70-57^16-33-22- 
73-62-49-38-25-14-  1-68-55-44-31-20- 
71-60-47-36-23-12-77-66-53-42-29-18- 


10-21-34^5-58-69-  4-15-28-39-52-63-76-9 
8-19-32-43-56-67-  2-13-26-37-50-61-74-7 
6-17-30-41-54-65-78-11 


Fig.  62 
TWO  CIRCUIT,  TRIPLE  WINDING. 


Fig.  63 
TWO  CIRCUIT,  QUADRUPLE  WINDING 


CHAP.  X.j 


TWO-CIRCUIT,   MULTIPLE-WOUND,   DRUM   ARMATURES. 


133 


Figure  63  is  a  six-pole,  two-circuit,  singly  re-entrant, 
quadruple  winding.  Symbolically  =  (QQQ).  n  =  6,  and  m  =  4. 
In  order  that  it  should  be  singly  re-entrant,  it  was  necessary 
for  the  greatest  common  factor  of  "y"  and  "m"  to  be  1. 
Therefore  "y"  was  taken  equal  to  7. 

C=ny±2  ra  =  6x7±2x4  =  34.  or  50. 

Fifty  conductors  have  been  taken. 

In  the  position  shown,  the  circuits  through  the  armature 
are :  — 


1_44_37_30- 
49^42-35-28- 
47-40^33-26- 


45-38-31-24-17-10-  3-4G-39-32 

8-15-22-29-36-43-^50-  7-14-21 

6-13-20-27-34-41-48-  5-12-19 

4-11-18-25— 

2-  9-16-23 


134 


ARMATURE   WINDINGS   OF   ELECTRIC   MACHINES. 


[CHAP.  x. 


Figure  64  is  a  six-pole,  two-circuit,  quadruply  re-entrant, 
quadruple  winding.  It  would  be  represented  symbolically 
as  O  O  O  O-  w  =  6,  and  ra  =  4.  In  order  that  it  should 
be  quadruply  re  entrant,  it  was  necessary  for  the  greatest 
common  factor  of  "  y  "  and  "  m  "  to  be  4.  Therefore  "  y  " 
was  taken  equal  to  8. 

4  =  40or  56. 


Fifty  -six    conductors  have  been   taken.      "  y  ''   is   alter- 
nately 7  and  9,  as  it  is  obviously  impossible  to  let  ^  =  8. 

In  the  position  shown,  the  circuits  through  the  armature 


are :  — 


55-48-39-32- 
53-46-37-30- 


3-52-13-36 
49^42-33-26-17-10-  1-50-11-34 

8-16-24-31-40^7-56-  7-16-23 

6-13-22-29^38-45-54-  5-14-21 

4-11-20-27— 

2-  9-18-25 


Fig.  64. 
TWO  CIRCUIT  QUADRUPLE  WINDING. 


JJU7BESITY] 


Fig.  65 
TWO  CIRCUIT,  QUADRUPLE  WINDING. 


CHAP.  X.] 


TWO-CIRCUIT,   MULTIPLE-WOUND,   DRUM   ARMATURES. 


137 


Figure  65  is  a  six-pole,  two-circuit,  doubly  re-entrant, 
quadruple  winding.  It  would  be  represented  symbolically 
a.s©©.  ?i  =  6,  and  m  =  -i.  In  order  that  it  should  be  doubly 
re-entrant,  it  was  necessary  for  the  greatest  common  factor 
of  "y"  and  "m"  to  be  2.  Therefore  "«/"  was  taken  equal 

to  10. 

<7=w/±2m=6xlO±2x4  =  52  or  68. 

Sixty-eight  conductors  have  been  chosen,  "*/"  is  alter- 
nately 9  and  11,  because  its  average  value,  being  even,  could 
not  be  used. 

The  two  independently  re-entrant  windings  have  been 
represented  respectively  by  light  and  by  heavy  lines. 

In  the  position  shown,  the  circuits  through  the  armature 
are :  — 

(  67-58-47-38 

63-54-43-34-23-14-  3-62-51-42 

65-56-45-36-25-16-  5-64-53-44 
61-52-41^32-21-12-  1-60^9-40 

10-19-30-39-50^59-  2-11-22-31 
6-15-26-35-46-55-66-  7-18-27 

8-17-28-37-48-57-68-  9-20-29 
4-13-24-33 


138 


AKMATUEE    WINDINGS   OF   ELECTRICAL   MACHINES. 


[CHAP.  x. 


Figure  66  is  a  six-pole,  two-circuit,  quadruply  re-entrant, 
quadruple  winding  [QOOO]-  «  =  6,  and  m  =  4.  In 
order  that  it  should  be  quadruply  re-entrant,  it  was  neces- 
sary that  the  greatest  common  factor  of  "y"  and  ''m" 
should  be  4.  Therefore  "y"  was  taken  equal  to  12. 

<7=wy±2»w  =  6xl2±2x4  =  64  or  80. 

Eighty  conductors  have  been  taken.  "  y  "  is  alternately 
11  and  13,  its  average  value  being  even. 

The  four  independently  re-entrant  windings  have  been 
represented  by  four  varieties  of  lines. 

In  the  position  shown,  the  circuits  through  the  armature 


are : 


77-66-63-42-29-18-  5-74-61-50 
75-64-51-40-27-16-  3-72-59^48 
73-62-49-38-25-14-  1-70-57^16 
71-60^7-36-23-12-79-68-55^4 

10-21-34-45-^58-69-  2-13-26-37 
8-19-32-43-^56-67-SO-ll-24-35 
6-17^30-41-54-65-78-  9-22-33 
4-15-28-39-52-63-76-  7-20^31 


N 


N 


Fig.  66 
TWO  CIRCUIT,  QUADRUPLE  WINDING. 


Fig.  67 
TWO  CFRCUIT,  QUADRUPLE  W1NDFNG. 


CHAP.  X.J 


TWO-CIRCUIT,  MULTIPLE-WOUND,   DRUM   ARMATURES. 


141 


Figure  67  is  a  six -pole,  two-circuit,  quadruply  re-entrant, 
quadruple  winding.  It  would  be  represented  symbolically 
as  O  O  O  O-  w  =  6,  and  m=4.  In  order  that  it  should  be 
quadruply  re-entrant,  it  was  necessary  that  the  greatest 
common  factor  of  "#"  and  "m"  should  be  4.  Therefore 
"  y  "  was  taken  equal  to  16. 

Cf=wy±2?w  =  6xl6±2x4  =  88  or  104. 

One  hundred  and  four  conductors  have  been  taken,  "y" 
is  17  at  the  front  end,  and  15  at  the  back  end,  thus  aver- 
aging 16. 

The  four  independently  re-entrant  windings  have  been 
represented  by  four  different  styles  of  lines. 

In  the  position  shown,  the  circuits  through  the  armature 
are :  — 


49-34-17-  2-89-74-57^12-25-  10- 
47-32-15-104-87-72-55-40-23-  8- 
45-30-13-102-85-70-53-38-21-  6- 


43-28-1 1-100-83-68-51-36-19-    4-91-76-59-44-27-12 

64-79-96-  7-24-39-56-71-88-103-16-31^8-63-80-95 

62-77-94-  5-22-37-54-69-86-101 

60-75-92-  3-20-35-52-67-84-  99 

58-73-90-  1-18-33-50-65-82-  97 


142 


AEMATUEE   WINDINGS   OF   ELECTEIC   MACHINES. 


[c'HAl'.  X. 


Figure  68  differs  from  Fig.  67  in  the  use  of  the  negative 
instead  of  the  positive  sign  in  the  formula.  It  is  given  to 
emphasize  the  fact  that  this  has  no  influence  on  the  type  of 
winding.  It  requires,  however,  a  greater  length  of  copper 
for  a  given  number  of  conductors.  Like  Fig.  67,  it  is  a 
six-pole,  two-circuit,  quadruply  re-entrant,  quadruple  wind- 
ing. •  It  would  be  represented  symbolically  as  O  O  O  O- 
w  =  6,  and  m  =  4.  In  order  that  it  should  be  quadruply  re- 
entrant, it  was  necessary  for  the  greatest  common  factor  of 
"  y  "  and  "  m  "  to  be  4.  Therefore  "  y  "  was  taken  equal 

to  16. 

Cf=m/±2TO=6xl6±2x4=:88or  104. 

Eighty-eight  conductors  have  been  taken,  "y"  is  17  at 
the  front,  and  15  at  the  back  end. 

The  four  independently  re-entrant  windings  have  been 
represented  by  different  kinds  of  lines. 

In  the  position  shown,  the  circuits  through  the  armature 


are:- 


I  58-73-  2-17-34-49-66-81 

56_71_88-15-32-47-64-79— 
54_G9-S6-13-30-i5-62-77— 
52-67-84-11-28-43-60-75-  4-19-36-61-68-83 


33-18-  1-74-57-12-25-10- 
35-20-  3-76-^9-44-27-12- 
37_22-  5-78-61-46-29-14- 


39_24-  7-80-63^8-31-16-87-72-55-40-23-  8 


N 


Fig.  68 
TWO  CIRCUIT,  QUADRUPLE  WINDING. 


N 


N 


N 

Fig.  69 
TWO  CIRCUIT,  SEXTUPLE  WINDING. 


CHAP.   X.] 


TWO-CIRCUIT,   MULTIPLE-WOUND,   DRUM   ARMATURES. 


145 


The  next  four  diagrams  (Figs.  69,  70,  71,  72)  form  a  group  of  sextuple  windings.  It  is  thought  that 
an  examination  of  this  group -will  bring  out  very  clearly  the  method  of  applying  and  the  interpretation  of 
the  rules  concerning  two-circuit,  multiple  windings.  The  following  table  will  be  of  assistance  in  studying 
them  :  — 


Figure. 

n 

V 

m 

a 

G.C.F. 
of  in  and  y. 

Name  of  Winding. 

Symbol. 

69 

6 

9 

6 

66 

3 

Two-circuit,  triply  re-entrant,  sextuple  winding. 

©©© 

70 

6 

10 

6 

72 

2 

Two-circuit,  doubly  re-entrant,  sextuple  winding. 

(55)  <SS> 

71 

6 

11 

6 

78 

1 

Two-circuit,  singly  re-entrant,  sextuple  winding. 

CPJOQQP) 

72 

6 

12 

6 

84 

6 

Two-circuit,  sextuply  re-entrant,  sextuple  winding. 

OOOOOO 

Figure  69  is  a  six-pole,  two-circuit,  triply  re-entrant,  sextuple  winding.  It  would  be  symbolically  repre- 
sented as  ©©©.  M  =  (>,  and  ?n  =  6.  In  order  that  it  should  be  triply  re-entrant,  it  was  necessary  that  the 
greatest  common  factor  of  u  m  "  and  "  y  "  should  be  3.  Therefore  "  y  "  was  taken  equal  to  9. 

6=42  or  66. 

Sixty-six  conductors  were  taken.  The  three  independently  re-entrant  windings  have  been  represented 
respectively  by  light,  heavy,  and  broken  lines. 

In  the  position  shown,  the  circuits  through  the  armature  are  :  — 

59-50-41-32-23-14-  5-62-53-44 

61-52-43-34— 

63-^54-45-36- 


-A 


65-56-47-38 
1-58-49-40 
3-60^51^12 


66-  9-18-27 

2-11-20-29 

4-13-22-31- 

6-15-24-33— 

8-17-26-35— 
10-19-28-^37-46-^55-64-  7-16-25 


146 


ARMATURE  WINDINGS  OF  ELECTRIC   MACHINES 


[CHAP.  x. 


Figure  70  is  a  six-pole,  two-circuit,  doubly  re-entrant, 
sextuple  winding.  It  would  be  represented  symbolically  as 
(55)  (55)  •  w  =  6,  and  m  =  6.  In  order  that  it  should  be 
doubly  re-entrant,  it  was  necessary  that  the  greatest  com- 
mon factor  of  "m"  and  "y"  should  be  2.  Therefore  "y" 
was  taken  equal  to  10. 


C=ny±  2  77i  = 


±2x6  =  48  or  72. 


Seventy-two  conductors  have  been  taken.  The  two  inde- 
pendently re-entrant  windings  have  been  represented  respec- 
tively by  full  and  dotted  lines. 

In  the  given  position,  the  circuits  through  the  armature 
are:  — 

63-54-43-34-23-14-  3-66-55-46  1 
65-56-45-36-25-16-  5-68-57-48 
67-58-47-38— 
69-60-49-10— 
71-62-51^2— 
1-64-53-44  --- 


2-11-22-31 

4-13-24-33— 

6-15-26-35— 

8-17-28-37— 
10-19-30-39— 
12-21-32-41-52-61-72-  9-20-29 


N 


67 


(66 


(64 


-.63 


(62 


59 


.4- 


57 


17 


\     55       . 
A54_. 


X 


19 


20\ 


21 


.5Q, 


-4-- 


-4- 


-r 


22\ 


23 


24 


25 


|48> 


261 


47x 


,x 


27N 


L46/ 


x 


39/  38j  37 


33\ 


32] 


X 


N 

Fig.  70 
TWO  CIRCUIT,  SEXTUPLE  WINDING. 


N 


N 

Fig.  71 
TWO  CIRCUIT.  SEXTUPLE  WINDING. 


N 


(JHA1-.  X.] 


TWO-CIRCUIT,   MULTIPLE-WOUND,   DKUM   AKMATUKES. 


149 


Figure  71  is  a  six-pole,  two- circuit,  singly  re-entrant, 
sextuple  winding.  It  would  be  represented  symbolically 
as  (QQQQQ).  n  =  (J,  and  ?n  =  G.  In  order  that  it  should  be 
singly  re-entrant,  it  was  necessary  that  the  greatest  common 
factor  of  "w"  and  "y"  should  be  1.  Therefore  "y"  was 
taken  equal  to  11. 

C=ny  ±  2  m  =  Q  x  11  ±  2  x  0  =  54  or  78. 

Seventy-eight  conductors  have  been  chosen. 
In  the  given  position,  the  circuits  through  the  armature 
are  :  — 

69-58-47-30-25-14-  3-70-59-48 
71-60-49-38-27-10-  5-72-61-50 


75-64-53-42- 

77-66-55-44- 

1-68-57-40- 


12-23-34-45-50-()7-78-ll-22-33 
10-21-32-43-54-65-76-  9-20-31 

8-19-30-41— 

6-17-28-39— 


2-13-24-;j5 


150 


AEMATUKE   WINDINGS   OF   ELECTRIC   MACHINES. 


[CHAP.  x. 


Figure  72  is  a  six-pole,  two-circuit,  sextuply  re-entrant, 
sextuple  winding.  It  would  be  represented  symbolically  as 
OOOOOO-  n  =  6,  and  m  =  6.  In  order  that  it  should 
be  sextuply  re-entrant,  it  was  necessary  that  the  greatest 
common  factor  of  "wi"  and  "#"  should  be  6.  Therefore 
"y"  was  taken  equal  to  12. 

C=ny  ±2m  =  6  x  12  ±  2  x  6  =  60  or  84. 

Eighty-four  conductors  have  been  taken. 

The  six  independently  re-entrant  windings  are  repre- 
sented respectively  by  different  styles  of  lines.  "#,"  of 
course,  is  taken  alternately  11  and  13. 

In  the  given  position,  the  circuits  through  the  armature 
are  :  — 

73-62-49-38-25-14-  1-74-61-50 
75-64-51-10-27-16-  3-76-63-52 
77-66-53-42-29-18-  5-78-65-54 
79-62^55-44 


81-70-57-46- 
83-72-59^8- 


12-23-36-47-60-71-84-11-24-35 
10_21^34-45-58-69-«2-  9-22-33 

8-19-32-43-56-67-80-  7-20-31 

6-17-30-41 

4_15_28-39— 

2-13-26-37 


*v 

^ 


rX/ 

^ 


/+- 


'/ 

?/     / 


x 


49/ 


'\ 


36) 


47  y 


46/ 


0\  39\- 


\/ 


N 


Fig.72 
TWO  CIRCUIT,  SEXTUPLE  WINDING. 


Fig.  73 
TWO  CIRCUIT,  DOUBLE  WINDING. 


CHAP.  X.] 


TWO-CIRCUIT,    MULTIPLE-WOUND,   DRUM   ARMATURES. 


153 


Figure  73  is  an  eight-pole,  two-circuit,  doubly  re-entrant,  double  winding. 
It  would  be  represented  symbolically  as  O  O-  w  =  8,  and  m  =  2.  In  order 
that  it  should  be  doubly  re-entrant,  it  was  necessary  that  the  greatest  com- 
mon factor  of  "wi"  and  "y"  should  be  2.  Therefore  "y"  was  taken  equal 

to  10. 

G=ny±  2  m=8xlO±  2x2  =  76  or  84. 

Eighty-four  conductors  have  been  taken. 

The  two  independently  re-entrant  windings  are  represented  respectively 
by  full  and  dotted  lines.  "«/"  is  taken  alternately  11  and  9,  the  average 
pitch  being  10. 

In  the  given  position,  the  circuits  through  the  armature  are:  — 

8-17-28-37-48^57-68-77-  4-13-24-33-44-53-64-73-84-  9-20-29-40-49-60-69  ] 
6-15-26-35-46-55-66-75-  2-11-22^31-42-51-62-71 


81-72-61-52^41-32-21-12-  1-76-65-56-45-36-25-16-  5-80- 
79-70-59^50-39^30-19-10-83-74-63-54-43-34-23-14-  3-78- 


154 


ARMATUKE   WINDINGS   OF   ELECTRIC   MACHINES. 


[CHAI-.  x. 


Figure  74  is  an  eight-pole,  two-circuit,  singly  re-entrant,  double  winding. 
It  would  be  represented  symbolically  as  ©.  n  =  3,  and  m  =  2.  In  order  that 
it  should  be  singly  re-entrant,  it  was  necessary  that  the  greatest  common 
factor  of  "y  "  and  "  m  "  should  be  1.  Therefore  "y  "  was  taken  equal  to  11. 

<7=My±2ra  =  8xll±2x2  =  84  or  92. 

Eighty -four  conductors  have  been  taken  just  as  in  the  preceding  figure. 
In  the  given  position,  the  circuits  through  the  armature  are  :  — 


8-19-30-41-52-63-74-  1-12-23-34^45-56-67 

6-17-28-39-50-61-72-83-10-21-32-43-54-65-76-  3-14-25-36-47-58-69- 


81-70-59-48^37-26-15-  4-77-66-55-44-33-22-11-84-73-62-51^40-29-18-  7-80 
79-68^57-46-35-24-13-  2-75-64-53-42-31-20-  9-82 


Fig.  74 
TWO  CIRCUIT,  DOUBLE  WINDING. 


IVSESi 


Fig.  75 
TWO  CIRCUIT,  DOUBLE  WINDING. 


CHAP,  x.]  TWO-CIRCUIT,  MULTIPLE-WOUND,   DKUM  AEMATURES.  157 


Figure  74  was  obtained  by  using  the  negative  sign  in  the 

formula  — 

C=ny  ±2m. 

This  is,  as  has  been  pointed  out,  rather  wasteful  of 
copper,  and  was  only  done  to  demonstrate  the  fact  that  in 
certain  cases  with  a  given  number  of  conductors,  either  a 
singly  or  a  doubly  re-entrant,  double  winding  may  be  used. 

In  Fig.  75,  the  positive  sign  was  used.  It  will,  however, 
not  be  necessary  to  analyze  it,  it  not  being  materially  dif- 
ferent from  Fig.  74. 


Numerous  interesting  deductions  concerning  two-circuit, 
multiple-wound,  drum  armatures  may  be  made  from  the 
data  contained  in  the  tables  in  Chapter  XVIII. 


CHAPTER  XI. 

THE   SAYERS  WINDING. 

THE  armature  coils  of  dynamos  have,  in  addition  to  their  function  of  establishing  the  electromotive  force 
required  external  to  the  armature,  the  function  of  setting  up  in  the  arc  of  commutation  an  electromotive  force 
to  reverse  the  current  in  them  as  they  successively  pass  the  collecting  brushes  (by  arc  of  commutation  is  meant 
the  arc  in  which  the  current  in  the  armature  coils  is  reversed,  the  extent  of  this  arc  being  determined  by  tin- 
length  of  the  arc  of  contact  of  the  collecting  brushes).  In  the  ordinary  methods  of  armature  winding  the 
electromotive  force  for  reversing  the  current  in  the  coils  is  obtained  by  giving  the  collecting  brushes  an  angular 
lead,  the  amount  of  which  depends  upon  the  distribution  of  the  magnetic  flux  in  the  air  gap,  the  coefficient  of 
self-induction  of  the  armature  coils  when  in  the  arc  of  commutation,  and  the  rate  of  change  of  the  current  in 
the  coils,  while  the  current  is  being  reversed.  In  generators  this  angular  lead  is  in  such  direction  that  the 
magnetomotive  force  of  the  armature  is  opposed  to  the  magnetomotive  force  of  the  field  magnets  to  an  extent 
proportional  to  the  angle  of  lead,  in  consequence  of  which  the  reversing  field  becomes  of  diminished  intensity 
for  an  increase  of  current  in  the  armature,  when  it  needs  to  be  increased. 

Mr.  Sayers,  of  Glasgow,  has  patented  a  winding  in  which  the  commutation  of  the  current  in  the  main 
armature  coils  is  effected  by  an  additional  set  of  coils  which  may  be  termed  commutating  coils.  These  coils 
are  applicable  to  any  form  of  armature  winding  suitable  for  commutating  machines.  One  of  these  coils  is 
connected  between  each  commutator  bar  and  the  connections  joining  the  main  armature  coils  in  series  with 
each  other.  These  commutating  coils  are  located  on  the  periphery  of  the  armature  in  such  a  position  with 
respect  to  the  main  coils  that  the  magnetomotive  force  of  the  main  coils  tends  with  increasing  current  to 
increase  the  flux  through  them,  and  further  so  that  the  magnetomotive  force  of  the  armature  acts  with  the 
magnetomotive  force  of  the  field  magnets  instead  of  against  it  as  in  ordinary  dynamos.  It  is  possible,  there- 
fore, through  a  certain  range  of  output  to  sparklessly  operate  a  generator  at  constant  voltage  without  changing 
the  lead  of  the  brushes  or  the  excitation  of  the  field  magnets.  It  may  be  noted  that  when  one  of  the  main 
coils  is  short-circuited  by  the  collecting  brushes  it  is  through  two  of  these  commutating  coils,  and  the  electro- 
motive force  from  these  coils  effective  for  reversing  the  current  in  the  main  coil  is  the  excess  of  the  electro- 
motive force  generated  in  the  leading  coil  over  that  in  the  following  coil.  The  position,  then,  of  the  reversing 
Held,  if  effective,  is  fixed  as  to  angular  extent  between  very  narrow  limits.  It  does  not  appear  to  the  writers 
that  the  reversing  field  can  be  so  localized  for  great  changes  of  current  in  the  armature  as  one  might  infer 
from  rending  the  discussion  of  Mr.  Sayers'  paper  at  the  Institution  of  Electrical  Engineers.  (See  Vol.  XXII., 
pages  377-441,  Journal  Ins.  Elect.  Engrs.,  London).  Within  certain  limits,  however,  it  appears  that  the 
magnetomotive  force  of  the  armature  may  be  utilized  in  creating  proper  strength  of  reversing  field. 

This  method,  as  applied  to  a  bi-polar  drum  winding,  is  illustrated  in  Fig.  76.  It  will  be  seen  to  consist  of 
a  regular  drum  winding,  with  the  difference  that  the  connections  from  the  winding  to  the  commutator  segments, 

158 


CHAP.   XI.] 


THE   SAYERS   WINDING. 


159 


instead  of  consisting  of  short  leads,  consist  of  auxiliary  force  conductors  which  pass  from  the  winding,  back- 
ward, a  short  distance  against  the  direction  of  rotation,  and  then  parallel  to  the  regular  face  conductors  to  the 
back  of  the  armature.  The  conductor  then  passes  forward  in  the  direction  of  rotation,  and  again  crossing  the 
armature,  is  carried  to  the  commutator  segment. 

In  the  diagram,  the  current  in  the  coil  A?  has  just  been  reversed.  The  coil  A1  is,  by  the  two  adjacent 
commutator  segments  under  the  brush,  short-circuited  while  its  main  conductors  are  still  moving  through 
intense  fields,  tending  to  maintain  the  current  in  its  original  direction.  But  this  short  circuit  contains,  in 
series  with  the  main  coil,  the  two  connections  to  the  commutator  segments,  both  of  which  are  so  linked  with 
the  magnetic  flux  from  the  pole  piece,  that  electromotive  forces  are  induced.  Of  the  electromotive  forces 
induced  in  the  two  commutator  loops,  that  in  the  loop  drawn  in  the  figure  is  added  to  that  of  the  short-cir- 
cuited main  coil,  but  this  loop  is  farther  out  of  the  magnetic  field  than  the  remaining  loop  (not  drawn)  of  the 
short-circuited  section.  This  latter_  loop,  leading  from  the  segment  next  adjacent  on  the  left  of  that  shown  at 


Fig.  76. 

(7,  being  well  under  the  pole  pieces,  has  induced  in  it  a  strong  electromotive  force,  which  opposes  that  in  the 
rest  of  the  short-circuited  section,  and  enables  a  current  to  be  generated  in  the  direction  of  that  in  the  half  of 
the  armature  circuit  of  which  it  is  soon  to  become  a  part. 

In  such  a  drum  winding,  Mr.  Sayers  refers  to  these  commutator  connections  as  "  reverser  bars."  As  they 
carry  the  current  only  during  the  short  time  that  their  corresponding  sections  are  passjng  under  the  brushes, 
they  may  be  of  much  smaller  cross-section  than  the  main  conductors. 

It  will  be  seen  from  the  above  description  that  the  winding  is  particularly  adapted  for  use  with  ironclad 
armatures  with  very  small  air  gaps,  for  the  effectiveness  of  the  arrangement  is  largely  dependent  upon  the 
differential  inductive  action  upon  two  successive  reverser  bars,  and  the  more  abrupt  the  demarcation  of  the 
magnetic  flux,  the  greater  will  be  this  differential  effect. 

It  should  be  clearly  understood  that  this  winding  is  equally  applicable  to  rings,  discs,  and  other  types  of 
armature. 


PART   II. 


WINDINGS  FOR  ALTERNATING-CURRENT   DYNAMOS   AND  MOTORS. 


CHAPTER   XII. 

ALTERNATING-CURRENT  WINDINGS. 

IN  general,  any  of  the  continuous-current  armature  windings  may  be  employed  for  alternating-current 
work,  but  the  special  considerations  leading  to  the  use  of  alternating  currents  generally  make  it  necessary  to 
abandon  the  styles  of  winding  best  suited  to  continuous-current  work,  and  to  use  windings  specially  adapted 
to  the  conditions  of  alternating-current  practice. 

Attention  should  be  called  to  the  fact  that  all  the  re-entrant  (or  closed  circuit)  continuous-current  wind- 
ings must  necessarily  be  two-circuit  or  multiple-circuit  windings,  while  alternating-current  armatures  may, 
and  almost  always  do  from  practical  considerations,  have  one-circuit  windings,  i.e.  one  circuit  per  phase.  From 
this  it  follows  that  any  continuous-current  winding  may  be  used  for  alternating-current  work,  but  an  alter- 
nating-current' winding  cannot  generally  be  used  for  continuous-current  work.  In  other  words,  the  windings 
of  alternating-current  armatures  are  essentially  non-re-entrant  (or  open  circuit)  windings,  with  the  exception 
of  the  ring-connected  polyphase  windings,  which  are  re-entrant  (or  closed  circuit)  windings.  These  latter  are, 
therefore,  the  only  windings  which  are  applicable  to  alternating-continuous  current,  commutating  machines. 

Usually,  high  voltages  are  desired,  and  in  such  cases  windings  are  generally  adopted  in  which  heavily 
insulated  coils  are  imbedded  in  slots  in  the  armature  surface.  Often,  for  single-phase  alternators,  one  slot  or 
coil  per  pole  piece  is  used,  as  this  permits  of  the  most  effective  disposition  of  the  armature  conductors  as 
regards  generation  of  electromotive  force.  If  more  slots  or  coils  are  used,  or,  in  the  case  of  face  windings,  if 
the  conductors  are  more  evenly  distributed  over  the  face  of  the  armature,  the  electromotive  forces  generated  in 
the  various  conductors  are  in  different  phases,  and  the  total  electromotive  force  is  less  than  the  algebraic  sum 
of  the  effective  electromotive  forces  induced  in  each  conductor.  But,  on  the  other  hand,  the  subdivision  of  the 
conductors  in  several  slots  or  angular  positions  per  pole,  or,  in  the  case  of  face  windings,  their  more  uniform 
distribution  over  the  peripheral  surface,  decreases  the  self-induction  of  the  windings  with  its  attendant  disad- 
vantages. It  also  utilizes  more  completely  the  available  space  and  tends  to  bring  about  a  better  distribution 
of  the  necessary  heating  of  core  and  conductors.  Therefore,  in  cases  where  the  voltage  and  the  corresponding 
necessary  insulation  "permit,  the  conductors  are  sometimes  spread  out  to  a  greater  or  less  extent  from  the 
elementary  groups  necessary  in  cases  where  very  high  potentials  are  used. 

Windings  in  which  such  a  subdivision  is  adopted,  will  be  referred  to  as  having  a  multi-coil  construction, 
as  distinguished  from  the  form  in  which  the  conductors  are  assembled  in  one  group  per  pole  piece,  which  latter 
will  be  called  uni-coil  windings. 

The  terms  uni-  and  multi-slot  have  been  applied  to  alternating-current  ironclad  armatures,  but  the  modified 
nomenclature  described  in  the  preceding  paragraph  will  be  preferable,  in  that  it  does  not  distinguish  between 
armatures  where  the  groups  are  arranged  on  the  periphery,  and  those  in  which  the  groups  are  imbedded  in 
slots.  A  little  consideration  will  show  the  advisability  of  this  nomenclature,  as  it  will  often  permit  one 
description  to  suffice  for  a  winding  which  may  be  used  either  for  ironclad  or  smooth-core  construction. 

163 


164  ARMATURE  WINDINGS   OF   ELECTRIC   MACHINES.  [CHAP.  MI. 

It  will  be  seen  later,  that  in  most  multiphase  windings,  multi-coil  construction  involves  only  very  little 
sacrifice  of  electromotive  force  for  a  given  total  length  of  armature  conductor,  and  in  good  designs  is  generally 
adopted  to  as  great  an  extent  as  proper  space  allowance  for  the  insulation  will  permit. 

Often  in  alternating  current  installations,  step-up  or  step-down  transformers,  or  both,  are  used,  and  in 
such  cases  the  other  extreme  is  approached,  and  the  apparatus  is  built  for  very  low  voltages.  This  permits 
the  use  of  very  small  space  for  insulation  ;  and  conductors  of  large  cross-section,  often  arranged  with  only  one 
conductor  per  group,  are  used.  Here  the  multi-coil  construction  is  less  difficult,  although  still  attended  to 
some  extent  with  the  disadvantage  of  obtaining  less  than  the  maximum  possible  voltage  per  unit  length  of 
armature  conductor. 

Examples  of  windings  adapted  respectively  to  both  of  the  above  extremes  will  be  given  in  the  following 
chapters. 

It  will  now  be  readily  understood  that  the  ordinary  continuous-current  windings  are  not,  in  the  great 
majority  of  cases,  adaptable  to  the  work  to  be  done.  They  should,  however,  always  be  kept  in  mind,  and  will 
often  be  found  to  work  in  nicely  in  special  cases. 

A  class  of  apparatus,  best  termed  alternating  continuous-current,  commutating  machines,  is  now  being 
found  of  much  value  in  various  ways.  They  are  in  a  general  way  used  for  feeding  continuous-current  circuits, 
from  single-phase  or  multiphase  circuits  (or  vice  versa),  and  also  sometimes  for  feeding  alternating  circuits 
of  one  class  (for  example,  single-  or  quarter-phase)  from  those  of  another  (say  three-phase).  This  type  of 
armature  may  usually  be  best  laid  out  by  employing  regular  continuous-current  windings  and  tapping  them 
off  in  the  proper  manner.  Examples  will  be  given. 

A  wide  variety  of  styles  of  armature  construction  have  been  employed  in  alternating-current  machinery. 
Rings,  drums  (both  ironclad  and  smooth-core),  discs,  and  very  many  other  types  have  been  successfully  built. 
Iron  cores  are  used  by  some  makers,  and  carefully  avoided  by  others.  Internal  and  external  rotating  parts 
have  each  found  advocates.  This  great  variety  renders  detailed  treatment  difficult,  and  in  the  following  dis- 
cussion it  has  been  generally  assumed  that  the  windings  are  >  laid  on  the  periphery  of  a  drum,  either  on  the 
surface,  or  imbedded  in  slots,  and  that  the  necessary  connections  are  made  at  the  ends  of  the  armature.  These 
peripheral  condflctors  are  represented  diagrammatically  by  radial  lines,  and  the  end  connections  by  crooked 
lines.  Thus,  re-entrant  polygons  drawn  with  heavy  lines  may  be  taken  to  represent  coils  of  the  desired 
number  of  turns,  the  lighter  lines  representing  the  connections  of  these  coils  to  each  other. 

In  the  case  of  bar  windings,  no  difficulty  will  be  found  in  understanding  the  diagrams,  as  they  correspond 
quite  nearly  to  the  continuous-current  windings.  Small,  heavy  circles  in  the  middle  of  the  diagram  represent 
collector  rings.  If  a  winding  is  desired,  for  a  disc  or  some  other  type,  the  diagrams  will  generally  be  found 
amply  suggestive.  Pancake  coils  and  other  types  of  windings,  not  specifically  described,  may  be  readily 
planned  by  slight  modifications  of  the  diagrams. 

No  examples  have  been  given  of  gramme-ring  alternating-current  windings,  as  these  may  be  found  in  text 
books,  and  are  so  easily  understood  as  to  require  no  discussion. 

Before  concluding  these  general  considerations,  it  is  desirable  to  emphasize  the  following  points  regarding 
the  relative  merits  of  uni-  and  multi-coil  construction  :  — 

With  a  given  number  of  conductors  arranged  in  a  multi-coil  winding,  less  terminal  voltage  will  be  obtained 
at  no  load  than  would  be  the  case  if  they  had  been  arranged  in  a  uni-coil  winding,  and  the  discrepancy  will  be 
greater  in  proportion  to  the  number  of  coils  into  which  the  conductors  per  pole  piece  are  subdivided,  assuming 
that  the  spacing  of  the  groups  of  conductors  is  uniform  over  the  entire  periphery. 

Thus,  if  the  terminal  voltage  at  no  load  be  taken  as  1  for  a  uni-coil  construction,  it  will,  for  the  same  total 
number  of  conductors,  be  .707  for  a  two-coil,  .667  for  a  three-coil,  .654  for  a  four-coil,  etc. 

But  when  the  machine  is  loaded,  the  current  in  the  armature  causes  reactions  which  play  an  important  part 


CHAP,  xii.]  ALTERNATING-CURRENT   WINDINGS.  165 

in  determining  the  voltage  at  the  generator  terminals,  and  this  may  only  be  maintained  constant  as  the  load 
comes  on,  by  increasing  the  field  excitation,  often  by  a  very  considerable  amount.  Now,  with  a  given  number 
of  armature  conductors,  carrying  a  given  current,  these  reactions  are  greatest  when  the  armature  conductors 
are  concentrated  in  one  group  per  pole  piece,  that  is,  when  the  uni-coil  construction  is  adopted,  and  they  decrease 
to  a  considerable  degree  as  the  conductors  are  subdivided  into  small  groups  distributed  over  the  entire  arma- 
ture surface,  that  is,  they  decrease  when  the  multi-coil  construction  is  used.  The  ratios  given  above  for  the 
relative  voltages  at  no  load,  for  uni-  and  multi-coil  construction,  do  not,  therefore,  represent  the  relative  values 
of  the  windings  under  working  conditions,  and  it  is  believed  that  careful  consideration  should  in  many  cases 
be  given  to  both  styles  of  winding,  before  deciding  upon  the  one  best  suited  for  the  purpose. 

Multi-coil  design  also  results  in  a  much  more  equitable  distribution  of  the  conductors,  and,  in  the  case  of 
ironclad  construction,  permits  of  coils  of  small  depth  and  width  which  cannot  fail  to  be  much  more  readily 
maintained  at  a  low  temperature  for  a  given  cross-section  of  conductor,  or,  if  desirable  to  take  advantage  of 
this  point  in  another  way,  it  should  be  practicable  to  use  a  somewhat  smaller  cross-section  of  conductor  for  a 
given  temperature  limit.  And  similarly,  when  we  consider  smooth-core  construction,  we  find  that  the  distribu- 
tion of  conductors  over  the  entire  surface  carries  with  it  great  advantages  from  a  mechanical  standpoint. 


UKI7BR3IT7 


CHAPTER    XIII. 

SINGLE-PHASE   WINDINGS. 

FIGURE  77  is  a  diagram  of  a  winding  for  single-phase 
alternating-current  generators  and  synchronous  motors, 
which  has  been  very  extensively  used.  It  has  one  group 
per  pole  piece,  consisting  of  adjacent  halves  of  two  coils  of 
the  proper  number  of  turns.  These  are  interconnected  as 
shown  by  the  light  lines.  The  adjacent  halves  of  the  two 
coils  are  usually  arranged  side  by  side,  but  it  might 
sometimes  be  of  advantage  to  place  them  one  over  the  other. 
The  arrangement  of  two  coils  side  by  side  has  been  satis- 
factorily applied  in  various  types  of  ironclad  armatures.  In 
Figs.  102  and  119  are  given  examples  of  this  style  of 
winding  connected  respectively  for  quarter-phase  and  for 
three-phase  work.  It  should  be  noted,  however,  that  the 
same  armature  can  be  used  for  three-phase  purposes  only  by 
having  fields  with  different  numbers  of  pole  pieces. 

The  avoidance  of  crossings  at  the  ends,  and  the  extreme 
simplicity  of  this  style  of  winding,  are  its  chief  advantages. 

166 


Fig.  77 


Fig.  78 


CHAP,  xiii.]  SINGLE-PHASE   WINDINGS.  169 


In  Fig.  78  is  given  another  uni-coil  winding,  but  here  only 
one  coil  is  placed  in  each  slot.  In  many  cases  this  might  be 
preferable  to  the  arrangement  shown  in  Fig.  77,  but  the  ends 
of  the  armatures  are  not  so  completely  occupied  by  the  ends 
of  the  coils,  which  wastes  room  and  tends  to  bring  about  a 
less  even  distribution  of  the  loss  by  heating.  The  use  of 
only  half  as  many  coils  is,  of  course,  generally  an  advantage, 
on  account  of  simplicity,  but  it  is  usually  necessary  for  each 
coil  to  be  wound  deeper,  which  is  objectionable  from  a 
thermal  standpoint,  as  well  as  from  the  fact  that  a  greater 
depth  of  space  has  to  be  allowed  for  the  winding  at  the  ends 
of  the  armature. 

It  should  not  be  overlooked  that  if  half  the  number  of 
pole  pieces  is  odd,  the  armature  coils  could  not  be  connected 
up  in  two  parallels,  which  would  in  practice  be  a  very 
considerable  objection,  as  it  would  limit  the  use  of  the 
armature  for  other  purposes  than  that  contemplated  in 
laying  out  the  original  design. 

One  feature  of  this  winding  worthy  of  consideration  is 
the  great  ease  of  insulation,  it  being,  in  this  respect,  superior 
to  Fig.  77,  one  of  the  groups  of  which  consists  of  adjacent 
halves  of  two  coils,  having  between  them  the  entire  voltage 
of  the  armature. 


UKI7BRSITY 


170  ARMATURE   WINDINGS   OF  ELECTRIC   MACHINES.  [CHAP.  xin. 


Figure  79  is  a  bar  winding,  with  one  bar  per  pole  piece, 
corresponding  to  the  coil  winding  of  Fig.  78.  This  would 
be  used  for  low  voltages,  and  in  the  case  of  generators  of 
large  capacity,  such  windings  are  practicable  for  high 
voltages.  It  is  typical  of  the  simplest  form  of  a  multipolar, 
single-phase  alternator,  and  has  been  used  in  some  very  large 
machines. 


Fig.  79 


Fig.  SO 


CHAP,  xiii.]  SINGLE-PHASE   WINDINGS.  173 


Figure  80  is  another  uni-coil  winding.  It  is  given  largely 
as  a  matter  of  interest ;  for,  as  will  be  seen,  it  has  undesir- 
able crossings  and  very  long  end  connections,  which  would  be 
very  wasteful  of  copper  unless  the  length  of  the  magnet 
cores  parallel  to  the  shaft  is  great  compared  with  the  length 
of  the  pole  arc.  Even  in  such  a  case  there  would  be  no 
advantage  over  Fig.  78,  unless  for  the  fact  that  Fig.  80  is  a 
very  good  winding  for  a  three-phase  alternator  of  one-third 
the  number  of  poles,  and  the  case  might  occur  where  it 
would  be  of  advantage  to  use  the  same  armature  and 
winding  for  both  cases.  This  would  make  an  excellent 
three-phase  winding  for  one-third  as  many  poles,  and  would 
then  be  similar  to  the  three-phase  winding  given  in  Fig.  116. 

The  corresponding  diagram  for  a  bar  winding,  with  one 
bar  per  pole  piece,  is  sufficiently  evident  from  Fig.  80,  and, 
in  view  of  its  unimportance,  will  not  be  given. 


174  ARMATURE   WINDINGS   OF   ELECTRIC    MACHINES  [CHAP.  xin. 


The  following  diagrams  are  multi-coil,  single-phase  alter- 
nators. As  a  class  they  have  been  very  thoroughly  discussed 
in  the  general  remarks  of  the  preceding  chapter. 


Figure  81  represents  a  very  simple  two-coil  winding.  It 
is  to  be  noted  that  this  winding  is  mechanically  identical, 
with  the  exception  of  the  interconnection  of  the  coils,  with 
the  winding  of  Fig.  78,  but  it  is  put  in  a  frame  with  half 
as  many  poles  as  there  are  groups  of  conductors,  instead  of, 
as  was  the  case  in  Fig.  78,  being  laid  out  for  a  frame  with  a 
number  of  poles  equal  to  the  number  of  groups  of  conductors. 


As  already  pointed  out,  such  multi-coil  windings  do  not  at 
no  load  generate  so  great  an  electromotive  force  per  unit  of 
length  of  face  conductor,  as  uni-coil  windings.  It  has,  how- 
ever, been  also  shown  on  page  164  that  this  objection  does 
not  have  such  great  weight  as  would  at  first  sight  appear  to 
be  the  case. 


Fig.  8  1 


Fig.  82 


CHAP,  xm.] 


SINGLE-PHASE   WINDINGS. 


177 


Figure  82  gives  a  bar  winding  with  two  bars  per  pole 
piece.  It  corresponds  to  the  coil  winding  of  Fig.  81. 
These  two  windings  (Figs.  81  and  82)  could  probably  be 
used  to  advantage  in  many  cases,  but,  of  course,  their  dis- 
advantages should  be  carefully  considered. 


178  ARMATURE  WINDINGS  OF   ELECTRIC   MACHINES.  [CHAI-.  xin. 


Figure  83  represents  another  two-coil  winding.  It  would 
seldom  be  used,  as  it  has  the  faults  and  lacks  the  merit  of 
the  winding  given  in  Fig.  81. 

If,  however,  the  coils,  instead  of  being  evenly  spaced, 
were  brought  into  groups  of  two,  not  very  far  apart,  it 
would,  to  some  extent,  have  part  of  the  advantages  of  the 
uni-coil  construction,  and  would  partly  overcome  some  of  the 
faults  of  the  latter.  If  modified  in  this  way,  it  would 
partake  of  the  nature  of  the  windings  given  in  Figs.  97,  98, 
and  99,  and  the  remarks  made  in  connection  with  these 
figures  should  be  referred  to. 


If  Figs.  81  and  82  should  be  similarly  treated  (that  is,  if 
the  coils  should  be  brought  into  groups  of  two  coils  each, 
not  very  far  apart),  the  result  would  be  a  winding  compa- 
rable to  those  given  in  Figs.  97  and  99. 


Pig.  83 


Fig.  84 


CHAP,  xiii.]  SINGLE-PHASE   WINDINGS.  181 


Figure  84  is  a  diagram  of  another  two-coil  winding.  It 
is  connected  as  a  single-phase  alternator,  but  except  for  the 
manner  of  interconnection  of  the  coils  it  is  identical  with 
the  quarter-phase  winding  given  in  Fig.  100.  It  will  give 
the  same  voltage  as  would  Fig.  100,  if  the  two  components 
of  the  quarter-phase  winding  should  be  connected  in  series. 

For  this  reason  (that  is,  because  when  reconnected,  it 
makes  a  good  quarter-phase  winding),  it  might  sometimes  be 
used,  but  of  course,  would,  as  stated  in  connection  with 
previous  windings,  require  a  greater  length  of  wire  to  gen- 
erate the  same  voltage  than  a  uni-coil  winding,  and  would 
naturally  have  a  greater  armature  self-induction.  But,  of 
course,  the  decrease  in  self-induction  due  to  the  multi-coil 
construction  would  somewhat  compensate  for  this  increase. 


182  ARMATURE   WINDINGS   OF  ELECTRIC   MACHINES.  [CHAP.  xin. 


Figure  85  gives  a  diagram  for  a  single-phase  bar  winding, 
corresponding  to  Fig.  84.  It  is  only  of  interest  as  showing 
that  it  is  identical  with  Fig.  82,  except  that  the  long-end 
connections  which  were  at  the  collector  ring  end  in  Fig.  82 
are  now  at  the  other  end. 

It  should  be  noted  that  all  these  multi-coil  windings  now 
under  consideration  would,  for  a  given  terminal  voltage, 
require  much  more  field  excitation  at  no  load  than  correspond- 
ing uni-coil  windings.  But  at  full  load  they  would,  in  some 
cases,  require  little  if  any  more  field  excitation  than  would 
be  the  case  with  uni-coil  windings.  As  a  result  of  these 
considerations  it  will  be  seen  to  be  necessary  in  any  par- 
ticular case  to  observe  the  requirements  for  the  field  exci- 
tation as  regards  permissible  regulation,  heating,  etc.,  when 
deciding  upon  the  type  of  armature  winding  to  adopt. 


Fig.  86 


ni.u-.  xiii.]  SINGLE-PHASE   WINDINGS.  185 


Figure  86  should  be  compared  with  Fig.  80.  It  is  quite 
like  the  latter,  except  that  it  has  two  coils  per  pole  piece 
instead  of  one.  It  would,  of  course,  not  be  used,  as  it  has 
such  long  end  connections. 

The  number  of  poles  is  sixteen.  Such  a  winding  with 
twelve,  eighteen,  or  twenty-four  poles  could  be  used  in  a 
three-phase  armature  of  one-third  the  number  of  poles  by 
merely  changing  the  interconnections  of  the  coils.  Figure 
123  gives  such  a  diagram  for  a  three-phase  alternator  in  an 
eight-pole  frame. 

The  mechanical  arrangement  of  such  windings  as  those 
given  in  Figs.  80,  86,  and  123  is  exceptionally  good, 
although  in  the  case  of  Figs.  80  and  86,  they  are  much  less 
simple,  as  single-phase  windings,  than  those  that  do  not 
cross. 


ISO  ABM1TUBE    WINDINGS   OF   KLKCTK1C   MACHINES.  [CIIAI-.  xni. 


Figure  87  represents  a  winding  with  two  groups  of  coils 
per  pole,  and  two  coils  per  group.  It  will  be  seen  to  lie  iden- 
tical with  the  two-phase  winding  of  Fig.  103,  except  that  it  in 
connected  up  as  a  single-phase  winding.  With  the  exception 
of  the  sequence  of  interconnection  of  the  coils,  it  may  be 
considered  to  bo  two  windings  like  Fig.  77,  one  of  which  is 
displaced  !)0°,  so  that  its  conductors  lie  half  way  between 
those  of  the  other. 

Its  end  connections  permit  of  good  mechanical  arrange- 
ment; very  much,  in  fact,  like  that  of  Figs.  80,  80,  and  123. 


?  e  n 


Fig.  88' 


CHAP,  xiii.]  SINGLE-PHASE   WINDINGS.  189 


Figure  88  shows  a  useful  three-coil  winding.  It  has  all 
the  advantages  and  disadvantages  already  noted  of  multi-coil 
armatures. 

The  end  connections  can  be  very  nicely  arranged,  so  as 
to  permit  of  winding  on  forms  and  slipping  them  into  slots. 
Only  two  different  shapes  of  forms  are  necessary  ;  one-half 
of  the  coils  would  be  wound  in  one  of  them,  and  the  rest 
in  the  other. 

It  will  be  seen  that  it  is  really  the  three-phase  winding  of 
Fig.  116  connected  up  as  a  single-phase  winding.  For  this 
reason,  among  others,  it  might  be  expected  to  be  of  service 
where  it  would  be  of  advantage  to  have  armatures  which 
could  be  used  interchangeably  for  single-  or  three-phase  work. 
Most  three-phase  windings  could,  of  course,  be  similarly 
used. 

As  a  single-phase  winding  per  se,  Fig.  88  is  excelled  by 
the  windings  of  Figs.  92  and  94,  which  require  a  smaller 
length  of  end  conductors. 


Of  TOT        x 

uiflTlRSITTs 


190  ARMATURE    WINDINGS   OF  ELECTRIC    MACHINES.  [CHAP.  xin. 


Figure  89  is  the  bar  winding  corresponding  to  the  coil 
winding  of  Fig.  88.  It  is  not  a  generally  useful  winding. 
Among  other  faults  it  has  three  different  lengths  of  end 
connections,  half  of  them  being  very  long.  In  this  respect 
it  is  excelled  by  the  winding  given  in  Fig.  93.  The  end 
connections  at  one  end  are  perfectly  regular,  but  this  would 
seldom  be  considered  to  compensate  for  the  needlessly  great 
length  of  copper  employed. 

This  winding  is  an  example  of  the  importance  of  thor- 
oughly examining  many  diagrams  before  adopting  a  winding 
for  a  certain  case  ;  for  it  is  not  at  once  apparent  that  this 
winding  could  be  improved  upon,  and  if  thought  of  first, 
might  be  chosen  without  further  investigation. 


Fig.  89 


Fig.  9O 


CHAP,  xiii.]  SINGLE-PHASE  WINDINGS.  193 


Figure  90  gives  a  coil  winding  very  similar  to  that  of 
Fig.  88.  But  the  end  crossings  would  render  it  very  incon- 
venient, and  the  space  at  the  ends  of  the  armature  is  not  so 
well  utilized  as  it  was  in  Fig.  88.  This  would  tend  to  an 
undesirable  concentration  of  the  heating. 

Unlike  Fig.  88,  the  winding  would  not  interfere  with  the 
armature,  being  made  in  segments  for  convenience  of  ship- 
ment. But  Figs.  92  and  94,  which  require  less  copper  in 
the  end  connections,  also  possess  this  advantage,  Fig.  94  to 
the  greatest  extent  of  all. 


194  AEMATUIiE  WINDINGS  OF  ELECTIUC  MACHINES.  [CHAP.  xm. 


Figure  91  has  all  the  faults  of  Figs.  89  and  90.  It  is  the 
bar  winding  corresponding  to  Fig.  90.  It  is  inferior  to  the 
winding  shown  in  Fig.  93. 

It  has  the  advantage  that  the  winding  is  more  symmet- 
rical as  a  whole  than  many  better  windings,  and  it  is  for  this 
reason  readily  constructed  and  connected  up,  with  little 
liability  of  error.  It  is  a  great  help  for  the  winder  to  be 
able  to  intelligently  perform  his  work,  and  windings  that 
are,  electrically  and  mechanically,  to  a  small  extent  inferior, 
might  in  some  cases  consistently  be  adopted  because  of  the 
simplicity  of  winding.  They  also  permit  of  the  more  ready 
locating  and  correcting  of  faults  that  are  liable  to  develop 
during  the  practical  operation  of  the  machinery. 


Fig.  92 


CHAP,  xiii.]  SINGLE-PHASE   WINDINGS.  197 


Figure  92  is  another  three-coil  winding.  It  gives  the 
same  results  as  Figs.  88  and  90,  but  with  less  copper,  as  it 
has  shorter  end  connections.  It  is  also  simpler,  as  there  is 
much  less  overlapping  at  the  ends.  Only  two  sizes  of  coils 
are  necessary. 

The  chief  point  of  inferiority  to  Figs.  88  and  90  is  that 
it  cannot  be  connected  up  as  a  three-phase  armature. 

Even  Fig.  92  is  not  so  good  as  Fig.  94  (to  be  described 
later),  which  latter  has  still  shorter  end  connections  and  less 
crossings. 

There  is  no  good  bar  winding  corresponding  to  Fig.  92. 

Figure  92  possesses  the  advantage  noted  in  the  discussion 
of  Fig.  90,  that  the  armature  may  be  built  and  shipped  in 
sections  without  interfering  with  the  winding. 


198 


ARMATURE    WINDINGS   OF   ELECTRIC   MACHINES. 


[CHAP.  xin. 


Figure  93  is  the  best  bar  winding  for  three  bars  per  pole 
piece.  It  is  distinctly  superior  to  Figs.  89  and  91,  as  it  has 
much  shorter  end  connections.  It  requires,  moreover,  only 
two  different  lengths  of  end  connections,  whereas  Figs.  89 
and  91  each  require  three. 


The  following  diagram  is  a  section  of  a  bar  winding  witli 
five  bars  per  pole  piece  :  — 


Fig.  93 


niXTl&SXTT 


Fig.  94 


CHAP,  xni.]  SINGLE-PHASE   WINDINGS.  201 


Figure  94  is  the  coil  winding  corresponding  to  the  bar 
winding  of  Fig.  93. 

This  coil  winding  is  superior  to  that  of  Figs.  88,  90,  and 
92,  in  that  it  gives  the  same  result  with  much  shorter  end 
connections  and  with  fewer  crossings  of  the  end  connections. 
Like  Fig.  92,  it  cannot  be  connected  up  as  a  three-phase 
alternator,  it  being  in  this  respect  inferior  to  Figs.  88 
and  90. 

The  winding  of  Fig.  94  could  readily  be  built  in  sections 
in  cases  where  it  would  be  necessary  to  ship  the  armature  in 
segments. 


202  AKMATURE   WINDINGS   OF   ELECTRIC   MACHINES.  [CHAP.  xin. 


Figure  95  is  a  coil  winding  electrically  equivalent  to 
Figs.  88,  90,  92,  and  94. 

Windings  of  this  class  may  readily  be  derived  from  the 
example  given  in  Fig.  95,  for  any  desired  number  of  coils 
per  pole  piece.  It  often  works  out  well  from  a  mechanical 
standpoint,  and  although  the  end  connections  are  necessarily 
longer  than  in  the  preceding  windings,  it  will  frequently  be 
found  useful. 

The  various  coils  might  with  advantage  be  grouped  to  a 
greater  or  less  extent,  in  accordance  with  the  principles 
exemplified  in  Figs.  97,  98,  and  99,  which,  together  with  the 
accompanying  text,  should  be  consulted  in  this  connection. 


Fig.  95 


Fig.  96  ' 


CHAP,  xin.]  SINGLE-PHASE   WINDINGS.  205 


Figure  96  gives  a  coil  winding  with  one  and  one-half 
coils  per  pole  piece.  It  has  two  coils  per  group.  It  is  really 
a  winding  such  as  Fig.  77,  put  in  a  field  with  two-thirds  as 
many  poles  as  the  armature  has  coils.  Thus  in  Fig.  96  there 
are  thirty  armature  coils  and  twenty  field  poles.  There  is 
disadvantageous  counter-induction  which  makes  the  use  of 
more  armature  copper  necessary  than  would  be  used  in  a 
uni-coil  winding.  The  armature  could,  however,  be  used 
interchangeably  in  fields  with  n  and  with  f  w  poles,  which 
property  permits  of  the  use  of  the  armature  in  cases  where 
different  speeds  or  periodicities  may  be  called  for. 

Also  by  changing  the  interconnections  of  the  coils,  an 
excellent  three-phase  armature  is  obtained.  The  three-phase 
connections  of  such  a  winding  are  given  in  Fig.  119. 

Moreover,  owing  to  the  fact  that  when  one  side  of  a  coil 
is  under  a  field  pole,  the  other  is  between  two  poles,  the  self- 
induction  of  such  a  winding  is  low,  and  is  fairly  uniform  for 
all  positions  of  the  armature. 


206  ARMATURE    WINDINGS   OF   ELECTRIC   MACHINES.  [CHAP.  xin. 


Many  of  the  multi-coil  windings  given  heretofore  have 
been  somewhat  undesirable  by  reason  of  the  counter-induc- 
tion, which  made  it  necessary  to  have  a  greater  length  of 
conductor  for  a  given  voltage  than  would  have  been  neces- 
sary if  the  conductors  had  been  concentrated  in  one  coil  per 
pole  piece. 

Figure  97  is  a  winding  which,  while  retaining  to  a  great 
extent  many  of  the  advantages  of  multi-coil  windings,  is 
usually  as  good  with  regard  to  its  freedom  from  counter- 
induction  as  a  uni-coil  winding  with  evenly  spread  coils. 

It  is  in  fact  one  of  the  two  windings  of  the  quarter-phase 
diagram  of  Fig.  104. 


Fig.  97 


CHAP,  xiii.]  SINGLE-PHASE   WINDINGS.  209 


Figure  98  does  not  differ  essentially  from  Fig.  97  as  far 
as  regards  the  point  that  it  is  intended  to  illustrate.  It, 
also,  is  one  of  the  two  windings  of  a  quarter-phase  armature, 
being  in  fact  derived  from  the  quarter-phase  diagram  of 
Fig.  112. 

Other  excellent  diagrams  of  this  type  may  be  derived  by 
considering  one  of  the  two  windings  of  the  quarter-phase 
armatures  shown  in  Figs.  105,  106,  107,  and  111. 


or 

UlflVBRSITT 


210  ABMATURE  WINDINGS  OF  ELECTRIC  MACHINES.  [CHAP.  xin. 


Figure  99,  like  its  predecessors,  Figs.  97  and  98,  has  its 
coils  arranged  in  groups  in  the  periphery  of  the  armature. 
It  has  to  some  extent  their  advantages  and  disadvantages. 
It  differs  from  them  in  utilizing  two-thirds  of  the  available 
space,  instead  of  one-half,  and  is  more  of  a  compromise  with 
the  uniformly  distributed  windings. 


It  is  obvious  that  windings  such  as  the  three  just  given 
may  readily  be  derived  from  any  of  the  evenly  distributed 
multiphase  windings  by  simply  discarding  one  or  more  of 
the  windings  belonging  to  the  respective  phases  of  such 
diagrams.  They  may  also  be  derived  from  many  of  the 
single-phase  windings  by  shifting  the  coils  laterally  from  the 
normal  position  into  the  desired  groups. 


Fig.  99 


Fig.  1  OO 


CHAPTER   XIV. 

QUARTER-PHASE  WINDINGS. 

FIGURE  100  represents  a  quarter-phase  coil  winding  with 
one  group  of  conductors  per  pole  piece  per  phase.  In 
accordance  with  the  nomenclature  already  adopted,  this 
would  be  known  as  a  uni-coil  winding ;  although  it  has  but 
one  coil  per  pole  piece  per  phase,  it  has  two  coils  per  pole 
piece. 

The  two  windings  are  represented,  respectively,  by  full 
and  broken  lines.  The  winding  is  quite  simple,  but  has  the 
objection  of  crossings  at  the  ends.  In  this  respect  it  is 
inferior  to  the  style  of  winding  represented  by  the  diagram 
of  Fig.  102. 

Three  collector  rings  could  be  used,  one  of  them  being 
common  to  each  winding.  In  the  diagrams,  however,  four 
collector  rings  will  be  shown,  this  being  the  method  now 
generally  used.  In  connection  with  a  system  employing 
three  collector  rings,  the  standard  quarter-phase  commu- 
tating  machines  (to  be  described  later)  could  not  be  used. 

213 


214  ARMATURE    WINDINGS   OF   ELECTRIC   MACHINES.  [CHAP.  xiv. 


Figure  101  is  the  bar  winding  corresponding  to  Fig.  100. 
It  does  not  well  utilize  all  of  the  available  space  on  the 
armature  ends.  This  is  generally  not  a  great  objection  in 
the  case  of  uni-coil  windings,  as  there  is  in  such  cases  plenty 
of  room  on  the  ends,  but,  other  things  being  equal,  it  is  of 
course  preferable  to  have  windings  uniformly  distributed 
at  the  ends  as  well  as  on  the  surface.  In  this  connection 
Fig.  109  should  be  studied,  and  it  will  be  seen  that  by 
placing  two  conductors  in  a  group  a  perfectly  symmetrical 
design  is  obtained  with  one  group  per  pole  piece. 

A  decided  objection  to  this  arrangement  would  be  that 
adjacent  conductors  would  have  between  them  large  differ- 
ences of  potential,  whereas  in  Fig.  101  there  are  but  few 
points  in  which  neighboring  conductors  have  between  them 
any  considerable  percentage  of  the  total  terminal  voltage. 


Fig.  1O2 


xiv.]  QUARTER-PHASE   WINDINGS.  217 


Figure  102  is  a  non-overlapping  quarter-phase  winding 
with  one  group  of  conductors  per  pole  piece  per  phase.  It  has 
the  advantage  over  Fig.  100  that  there  are  no  crossings 
at  the  ends  of  the  armature,  and  that  it  utilizes  the  end  space 
more  completely,  thus  bringing  about  a  better  distribution  of 
the  necessary  heating  losses  in  the  copper.  Its  chief  fault  is 
that  if  the  width  of  the  pole  face  is  over  one-half  of  the 
distance  between  pole  centers,  the  coils  never  embrace  the 
total  flux  from  one  pole  piece.  However,  at  full  load,  the 
area  occupied  by  the  flux  is  narrower,  and  a  greater  portion 
would  be  included  than  at  no  load,  so  that  this  objection 
would  not  be  so  serious  as  would  appear  at  first  sight. 
Moreover,  the  necessary  space  allowance  for  the  field 
winding  will  in  many  cases  not  permit  the  width  of  the  pole 
piece  to  be  sufficiently  great  to  cause  any  trouble  in  this 
respect.  Mechanically,  this  is  an  excellent  winding,  being, 
in  fact,  the  single-phase  winding  given  in  Fig.  77,  for  double 
the  number  of  poles. 

The  remarks  made  in  connection  with  Fig.  96  (single- 
phase  alternating  winding  with  one  and  one-half  slots  per 
pole  piece)  should  also  be  considered  in  studying  this  wind- 
ing. Consult  also  Fig.  119  and  corresponding  text. 


218  ABMATURE   WINDINGS   OF   ELECTEIC   MACHINES.  [CHAP.  xiv. 


Figure  103,  which  like  Fig.  102  has  two  coils  per  group, 
is  not  open  to  the  objection  discussed  on  the  preceding  page. 
It  has,  however,  crossings  at  the  ends.  It  is  to  be  preferred 
to  Fig.  100  for  the  reason  that  the  end  space  is  more 
effectively  utilized,  but  the  additional  crossings  would 
require  a  somewhat  greater  length  of  wire  than  would  be 
necessary  in  Fig.  100. 

Bar  windings  could  be  built  corresponding  to  the  coil 
windings  of  Figs.  102  and  103.  They  would  not  be 
symmetrical  at  both  ends,  but  might  advantageously  prove 
applicable  for  certain  cases.  The  two  bars  of  a  group  could 
be  placed  either  over  each  other,  or  side  by  side.  With 
smooth-core  construction  the  latter  arrangement  would  be 
adopted,  and  often  also  in  ironclad  armatures  with  bar 
windings. 


Fig.  1  O3 


Fig.  104 


xiv.]  QUARTER-PHASE    WINDINGS.  221 


Figure  104  is  a  quarter-phase  coil  winding  with  two  con- 
ductors per  pole  piece  per  phase.  It  is  entirely  symmetrical, 
and  utilizes  all  the  winding  space  to  the  best  advantage.  The 
crossings  at  the  ends  are  unavoidable,  but  may  be  made 
thoroughly  satisfactory  from  a  mechanical  standpoint  by 
preceding  in  the  manner  shown  most  clearly  in  the  diagram 
of  Fig.  123. 

Such  windings  are  applicable  to  quarter-phase  armatures 
with  any  even  number  of  coils  per  pole  piece  per  phase. 

In  studying  Fig.  104  it  will  be  instructive  to  examine 
Fig.  97,  which  is  one  of  the  two  windings  of  Fig.  104. 


222  ARMATURE   WINDINGS   OF   ELECTRIC   MACHINES.  [CHAP.  xiv. 


Figure  105  is  electrically  equivalent  to  Fig.  104.  The 
winding  might  sometimes  be  used,  although  it  would  for 
most  purposes  be  excelled  by  Fig.  104. 

It  will  be  noted  that  the  end  connections  are  longer,  and 
that  they  occupy  a  greater  depth.  Much  of  the  end  space 
is  wasted.  This  winding  is  superior  to  that  of  Fig.  104,  in 
that  the  coils  are  so  located  as  to  make  it  very  plain  how  the 
connections  should  run.  This  would  be  of  great  assistance 
to  the  winder,  and  would,  moreover,  facilitate  the  detection 
and  correction  of  faults  that  might  develop  in  practical 
working. 

An  armature  with  such  a  winding  could  be  built  and 
shipped  in  segments. 


Fig.  105 


Fig.  1  O6 


CHAP,  xiv.]  QUAETEE^PHASE   WINDINGS.  225 


Figure  106  is  a  bar  winding  differing  but  little  in  princi- 
ple from  the  coil  winding  of  Fig.  105.  The  space  is  uni- 
formly* occupied  at  the  collector  ring  end,  but  is  not  at  the 
other  end. 

This  lack  of  uniformity  in  end  connections  is  not  of  very 
great  moment  in  bar  windings  with  few  bars  per  pole  piece. 
Other  things  being  equal,  however,  it  would  on  the  whole 
seem  best  to  avoid  it,  although  in  special  cases  such  disposi- 
tion of  the  end-connections  allows  room  much  needed  for 
mechanical  arrangements. 


UNIVERSITY 


226  ARMATURE  WINDINGS  OF  ELECTRIC   MACHINES.  [CHAP.  xiv. 


Figure  107  is  a  bar  winding  corresponding  to  Fig.  104. 
It  is  a  good  example  of  the  fact  that  very  symmetrical  coil 
windings  often  correspond  to  very  unsymmetrical  bar  wind- 
ings, and  vice  versa.  But,  as  noted  on  the  preceding  page, 
this  lack  of  symmetry  is  in  such  cases  not  a  great  objection, 
and  has,  incidentally,  some  redeeming  features. 

One  of  the  two  windings  of  this  diagram  would,  as  men- 
tioned on  page  209,  work  out  very  well  for  a  single-phase 
armature. 


Fig.  107 


Fig.  1  O8 


CHAP,  xiv.]  QUARTER-PHASE   WINDINGS.  229 


Figure  108  is  a  much  better  bar  winding  than  Fig.  107, 
though  electrically  equivalent. 

It  will  be  seen  to  be  unsymmetrical  at  two  points  at  the 
end  distant  from  the  collector  This  irregularity  consists  in 
the  end  connections  of  the  two  adjacent  bars  starting  off  in 
the  same  direction,  instead  of,  as  in  all  other  parts  of  the 
winding  except  these  two,  going  in  opposite  directions. 
Four  of  the  end  connections  have  to  be  longer  than  the  rest. 

This  winding  is  practically  the  same  as  the  following 
one,  Fig.  109,  except  that  the  above -described  irregularity 
is  introduced  instead  of  making  use  of  the  cross-connections 
shown  in  Fig.  109. 


VIZTlRSZT'y 


230  AKMATUKE  WINDINGS  OF  ELECTEIC   MACHINES.  [CHAP.  xiv. 


Figure  109  is  a  symmetrical  quarter-phase  bar  winding  with  two  con- 
ductors per  pole  piece  per  phase.  If  used  for  an  ironclad  or  projection 
armature,  it  may  have  four  slots  per  pole  piece  with  one  conductor  per  slot, 
or  two  slots  per  pole  piece  with  two  conductors  per  slot. 

Examination  will  show  that  it  is  essentially  a  twelve-pole  armature  with 
four  separate  series  of  windings  of  twelve  bars  each.  These  four  wind- 
ings are  connected  up  into  two  windings  of  twenty-four  conductors  each. 

At  the  front  end  y  =  5,  and  at  the  back  end  y=3,  therefore  average 
y=4. 

As  pointed  out  in  the  discussion  of  Fig.  101,  Figs.  108  and  109  have 
the  fault  that  neighboring  conductors  have  between  them  large  percent- 
ages of  the  total  potential  of  the  armature,  and  this  would  sometimes  be 
objectionable  in  cases  of  high  potential  windings. 


It  will  doubtless  have  been  observed  that  in  the  case  of  quarter-phase 
windings,  multi-coil  construction  does  not  have  to  so  great  an  extent  the 
fault  pointed  out  in  the  case  of  corresponding  single-phase  windings,  of 
useless  counter-electromotive  forces. 

The  coils  of  one  phase  usually  embrace  practically  the  entire  flux, 
because  the  two  groups  of  conductors,  forming  respectively  the  two  sides 
of  a  coil,  are  usually  separated  by  a  group  forming  one  side  of  a  coil 
belonging  to  the  winding  of  the  other  phase. 

This  advantage  is  possessed  in  a  still  greater  degree  by  the  three-phase 
windings,  which  will  be  discussed  later. 

Exceptions  to  the  above  statement  often  occur  in  cases  where  single 
and  multi-phase  alternating  windings  are  obtained  from  ordinary  direct- 
current  windings. 


Fig.  1O9 


CHAP,  xiv.] 


QUARTER-PHASE   WINDINGS. 


233 


Figure  110  represents  a  quarter-phase  coil  winding  with 
three  slots  per  pole  piece  per  phase.  It  does  not  utilize  very 
uniformly  the  end  space  on  the  armature,  the  end  connec- 
tions being  three  layers  deep  at  some  points  and  much  less 
at  others. 

An  advantage  of  this  winding  is  the  well-defined  nature 
of  the  coils,  rendering  it  easy  to  see  just  how  they  should  be 
connected.  The  winding  might  also  be  necessary,  if  it 
should  be  required  that  the  armature  should  be  built  so  that 
it  could  be  shipped  in  segments. 


234  ARMATURE   WINDINGS   OF   ELECTRIC   MACHINES.  [CHAP.  xiv. 


Figure  111  is  electrically  equivalent  to  Fig.  110,  but 
the  end  connections  are  only  two  layers  deep,  are  shorter, 
and  are  better  distributed  over  the  ends  of  the  armature. 
Where  the  number  of  coils  per  pole  piece  per  phase  must 
be  odd,  windings  such  as  those  given  in  Figs.  110  and  111 
must  for  quarter-phase  armatures  often  be  chosen.  It  is 
quite  apparent  that,  except  in  special  cases,  the  style  of 
diagram  shown  in  Fig.  Ill  will  give  the  best  result. 


Fig.  1  1  1 


Fig.  1  1  2 


CHAP,  xiv.]  QUARTER-PHASE   WINDINGS.  237 


Figure  112  is  a  bar  winding  corresponding  to  the  coil 
winding  of  Fig.  111.  Although  not  symmetrical,  the  end 
connections  are  fairly  well  distributed,  and  there  would  be 
in  but  very  few  places  any  great  percentage  of  the  total 
difference  of  potential  between  adjacent  conductors.  Several 
different  lengths  of  end  connections  would  necessarily  have 
to  be  employed. 

One  of  the  two  windings  of  this  diagram  has  already 
been  given  in  Fig.  98  in  Chapter  XIII.  on  Single-Phase 
Windings. 


><»•*  OF  Tar 


238  ARMATURE  WINDINGS  OF  ELECTRIC  MACHINES.  [CUAJP.  xiv. 


Figure  113  represents  a  quarter-phase  bar  winding  with 
four  conductors  per  pole  piece  per  phase.  It  is  perfectly 
symmetrical,  and  may  have  one,  two,  or  four  conductors  per 
slot,  as  desired. 

This  winding  is  like  that  of  Fig.  109,  except  that  four 
sets  of  elementary  windings  are  connected  in  series  to  form 
one  of  the  two  phases,  instead  of  two  sets,  as  was  the  case 
in  Fig.  109. 

If  one-half  or  one-quarter  as  great  a  terminal  electro- 
motive force  should  be  desired,  two,  or  all  four,  of  these 
elementary  windings  could  be  connected  in  parallel  between 
the  collector  rings,  instead  of  joining  them  in  series  as 
shown. 


W1VIRSIT7 


CHAP,  xiv.]  TWO-CIRCUIT  WINDING  FOR  COMMUTATING  MACHINES.  241 


TWO-CIRCUIT  WINDING  FOR  QUARTER-PHASE  CONTINU- 
OUS CURRENT  COMMUTATING  MACHINE. 

Figure  114  is  the  diagram  for  the  winding  for  a  commu- 
tating  machine  for  deriving  a  continuous  current  from  a 
quarter-phase  alternating  supply,  or  vice  versa,  or  for  a 
generator  for  supplying  both  continuous  and  quarter-phase 
systems. 

Examination  will  show  that  it  is  the  two-circuit  single 
winding  of  Fig.  43  (Chap.  VIII.),  tapped  off  from  four 
approximately  equidistant  points  to  four  collector  rings. 
As  the  winding  consists  of  sixty-eight  conductors,  there 
should  be  seventeen  conductors  in  each  section,  but  for  the 
convenience  of  having  all  the  connections  to  the  collector 
rings  made  at  one  end,  the  divisions  are  16,  16,  18,  and  18. 
With  the  large  numbers  of  conductors  used  in  practice,  the 
irregularity  produced  by  one  conductor  more  or  less  would 
be  of  less  importance,  though  always  undesirable.  In  such  a 
winding  four  points  only  of  the  armature  are  tapped  inde- 
pendently of  the  number  of  poles. 


Of  TH3      v 

TOIXTIBSXTT! 


242  ARMATURE   WINDINGS   OF   ELECTRIC   MACHINES.  [CHAP.  xiv. 


TWELVE-CIRCUIT  WINDING  FOR    QUARTER-PHASE   CON-  , 
TINUOUS-CURRENT  COMMUTATING  MACHINE. 

Figure  115  is  another  winding  for  a  quarter-phase 
continuous-current  commutating  machine.  It  is  funda- 
mentally a  multiple-circuit,  continuous-current  winding, 
and  requires  four  leads  (one  to  each  collector  ring)  for 
each  pair  of  poles. 


It  is  to  be  remembered  that  in  quarter-phase  continuous- 
current  commutating  machines,  the  effective  voltage  between 
collector  rings  180°  apart  equals  the  continuous-current 
voltage  multiplied  by  .707  (or  divided  by  1.414). 


Fig.  1  1  5 


Fig.  1  16 


CHAPTER    XV. 

THREE-PHASE  WINDINGS. 

FIGURE  116  is  a  three-phase  coil  winding  with  one  set  of  conductors  per  pole  piece  per  phase.  The  coils 
belonging  to  the  three  windings  may  be  distinguished  from  each  other  by  the  three  different  styles  of  lines. 
The  armature  is  connected  in  a  manner  technically  known  as  the  "  Y  "  connection.  The  characteristic  of  this 
style  of  connecting  three-phase  windings  is  that  one  end  of  each  of  the  three  windings  is  brought  to  a  common 
connection,  the  other  three  ends  being  carried  to  three  collector  rings. 

Inasmuch  as  three-phase  alternators  have  but  recently  been  used  to  any  considerable  extent  in  practice,  it 
may  not  be  out  of  place  to  give  as  concisely  as  possible  a  few  of  the  leading  considerations  involved  in  their 
practical  construction  and  operation,  as  far  as  relates  to  the  armature  windings. 

One  complete  cycle  is  passed  through  by  any  armature  conductor  while  passing  from  a  certain  point 
opposite  one  pole  piece,  say  the  middle  of  the  north  pole,  to  the  corresponding  point  opposite  the  next  pole 
piece  of  the  same  polarity.  This  angular  distance  is  usually  spoken  of  as  360°,  independently  of  the  number 
of  poles  of  the  machine.  Now,  a  three-phase  armature  winding  is  merely  three  single-phase  windings,  laid 
on  the  same  armature,  the  conductors  of  the  three  windings,  however,  being  located  120°  (one-third  of  a 
cycle)  behind  each  other.  Any  conductor  of  one  winding  is,  therefore,  at  any  instant,  in  a  different  phase 
from  that  of  the  conductors  of  the  other  windings.  Thus,  in  the  position  represented  in  Fig.  116,  the 
conductors  represented  by  heavy  lines  are  directly  opposite  the  middle  of  the  pole  pieces,  the  light  line 
conductors  are  located  120°  behind  them,  and  the  dotted  conductors  are  120°  behind  the  light  conductors  and 
240°  behind  the  heavy  conductors. 

Now  it  follows  from  the  relative  positions  of  the  conductors  .of  the  three  phases,  that  the  electromotive 
forces  generated  in  the  three  windings  are  120°  behind  each  other,  and  if  they  are  sine  waves,  they  may  be 
represented,  as  in  the  following  figure,  by  three  sine  curves  displaced  120°  behind  each  other. 


If  the  three  circuits  are  equally  loaded,  these  curves  may  also  be  considered  to  represent  the  corresponding 
instantaneous  values  of  the  current. 

245 


246  ARMATURE   WINDINGS   OF   ELECTRIC   MACHINES.  [OHAI>.  xv. 

It  will  be  noted  that  at  every  instant,  the  algebraic  sum  of  the  three  currents  is  zero.  Now  instead  of 
having  three  pairs  of  lines  and  brushes  and  collector  rings,  one  end  of  each  of  the  three  windings  is  brought 
to  a  common  connection,  and  a  conductor  from  this  common  connection  could  be  used  as  a  common  return  for 
each  of  the  three  circuits.  But,  since  the  resultant  current  at  every  instant  is  zero,  this  conductor  becomes 
superfluous  and  is  omitted. 

If  the  voltage  between  any  ring  and  the  common  connection,  that  is,  the  voltage  per  phase,  is  equal  to  v, 
then  the  volts  V  between  any  pair  of  collector  rings  will  be,  — 

V=  V3  v  or  1.732  v. 

The  effective  current  will  be  equal  in  each  of  the  three  lines,  and  may  be  represented  by  0. 
With  a  non-inductive  load,  the  watts  output,  W,  will  be,  — 

»1.782  CV. 


V3 

If  the  load  is  inductive,  the  current  C,  for  a  given  output  TF,  will  be  greater  than  with  a  non-inductive 
load. 

A  safe  and  easily  understood  way  of  connecting  the  three  windings  correctly  to  the  three  collector  rings 
and  the  common  connection,  is  to  consider  that  the  winding  whose  conductors  occupy  the  position  in  the 
middle  of  the  pole  piece,  is  carrying  the  maximum  current,  and  to  indicate  its  direction  on  the  winding 
diagram  by  an  arrow.  The  currents  at  the  same  instant  in  the  conductors  immediately  next  to  it  on  the  right 
and  left  are  in  the  same  direction,  and  should  be  so  marked  by  arrow-heads.  Now,  from  the  sine  curves  given 
above,  it  will  be  seen  that  where  one  curve  has  a  maximum  value,  the  other  two  have  a  value  half  as  great, 
and  in  the  opposite  direction.  Therefore  consider  that  the  current  in  the  winding  occupying  the  position 
at  the  middle  of  the  pole  face  is  flowing  away  from  the  common  connection.  Then  the  currents  in  the  other 
two  windings,  which  are  each  of  half  the  magnitude  of  the  former,  must  both  be  flowing  into  the  common 
connection  ;  therefore  join  those  ends  of  the  three  windings  to  the  common  connection,  which  will  bring  about 
this  condition  at  this  instant.  Carry  the  other  three  ends  to  the  three  rings.  This  has  been  done  in  the 
upper  diagram  of  Fig.  117,  which  represents  a  "  Y  "  connected  three-phase  winding. 

Another  way  of  connecting  up  three-phase  armatures  is  to  connect  the  three  windings  in  series  in  a  closed 
circuit,  and  at  every  third  of  the  total  way  through  the  circuit  thus  formed,  to  carry  off  a  lead  to  one  of  the 
collector  rings. 

In  the  case  of  this,  technically  called  the  "delta"  (A)  connection,  the  current  0  in  the  line  (i.e.  beyond 
the  collector  rings)  is  (7=V3e,  or  CY=1.732e,  where  c  =  current  in  the  winding.  The  volts  per  winding  are 
in  this  case  equal  to  the  volts  between  each  pair  of  collector  rings  ;  that  is,  to  the  volts  per  phase.  The  watts 
output  of  a  machine  are,  — 


W=  3  cV=  --       =  1  .  732  CV. 

V3 

Examples  of  each  of  these  two  connections  are  given  in  Fig.  117. 

The  upper  diagram  represents  a  "  Y  "  connected  three-phase  armature,  and  the  lower  diagram  represents 
the  very  same  armature,  but  with  a  "delta"  (A)  connection. 

In  connecting  up  the  separate  windings  for  a  "delta"  (A)  connection,  it  is  most  convenient  to  choose 
the  instant  when  the  conductors  of  one  phase  are  opposite  the  middle  of  a  pole  piece.  Then  assume  these 
conductors  to  be  carrying  the  maximum  current,  which  is  illustrated  in  the  figure  by  the  larger  arrow-head. 


Fig.  1  1  8 


CHAP.  XV.] 


THREE-PHASE    WINDINGS. 


249 


The  other  two  windings  are  at  the  same  instant  having  induced  in  them  currents  of  only  one-half  this 
magnitude.  The  condition  of  affairs  in  line  and  in  winding  is,  for  the  instant,  as  represented  in  the  follow- 
ing diagram. 

From  this  it  is  seen,  that,  starting  from  the  middle  collector  ring 
(corresponding  to  point  a  in  the  diagram),  and  following  the  direction 
of  the  current,  we  must  pass  through  the  heavy  winding,  carrying 
the  large  current  to  the  outer  ring  (corresponding  to  point  b  of 
diagram).  In  the  other  direction,  we  must  pass  from  the  middle 
ring  (i.e.  point  a),  through  the  dotted  winding,  which  carries  one- 
half  as  great  a  current,  to  the  inner  collector  ring  (corresponding  to 
point  c  of  diagram).  Then  we  must  continue  through  the  light  wind- 
ing, still  in  the  direction  of  the  current,  until  we  again  reach  the  outer 
collector  ring,  or  point  b  of  diagram. 

Any  of  the  following  three-phase  diagrams  may  be  connected 
either  "  delta  "  or  "  Y,''  but  they  will  usually  be  shown  with  the  ••  Y  " 
connection. 

It  is  well  to  keep  in  mind  that  if  a  "  Y  "  connected  armature  is  changed  over  to  the  "  delta  "  connection,  it 

may  with  the  same  regulation  and  heating  give  1.732  times  as  much  current,  but  only  1  7QO  times  the  voltage. 
The  reverse  holds  true  in  changing  from  "delta"  (A)  to  "Y." 


1.732 


Figure  118  is  the  bar  winding  corresponding  to  Fig.  116.  It  has  one  bar  per  pole  piece  per  phase.  This 
winding,  while  partaking  of  all  the  advantages  and  disadvantages  of  multi-coil  construction,  would  be 
particularly  unsatisfactory  for  a  three-phase  motor  on  account  of  the  dead  points  that  it  would  develop  at 
starting.  These  dead  points  are  much  less  marked  with  multi-coil  windings  and  with  windings  like  those  in 
Figs.  119  and  120. 

In  the  case  of  induction  motors,  it  is  customary  to  make  use  of  such  windings  as  those  given  in  Figs.  126 
and  127,  where  smoother  action  is  obtained  partly  by  virtue  of  the  choice  of  a  number  of  conductors,  prime,  or 
nearly  so,  to  the  number  of  poles. 


250  ARMATURE  WINDINGS  OF  ELECTRIC  MACHINES.  [CHAP.  xv. 


Figure  119  is  a  non-overlapping,  three-phase,  coil  wind- 
ing, with  only  one  and  one-half  coils  per  pole  piece  per 
phase.  It  is  the  winding  which  was  given  with  its  single- 
phase  connection,  in  Fig.  96.  This  should  make  a  very 
excellent  three-phase  winding,  as  there  is  no  crossing  of 
the  coils.  It  is  a  regular  thirty-pole,  single-phase  winding, 
connected  up  as  a  three-phase  armature  for  twenty  poles. 
This  diagram  should  be  compared  with  Fig.  77,  Fig.  96,  and 
Fig.  102.  It  should  be  particularly  suitable  for  use  in  three- 
phase  motor  work,  as  it  should  have  very  weakly  defined 
dead  points.  In  a  projection  armature,  when  a  slot  is 
opposite  a  certain  pole  piece,  spaces  between  two  slots  will 
be  opposite  the  adjacent  pole  pieces,  thus  giving  a  more 
equitable  distribution  of  the  magnetic  flux. 

The  inductance  of  such  a  winding  is  low  and  fairly 
uniform,  for  the  reason  that  when  one  side  of  a  coil  occupies 
a  position  under  a  pole  piece,  the  other  side  of  the  coil  is 
between  two  pole  pieces. 


Fig.  1  1  9 


Fig.  1  2O 


CHAI-.  xv.]  THKEE-PHASE   WINDINGS.  253 


Figure  120  represents  the  corresponding  bar  winding. 
In  the  case  of  projection  or  ironclad  armatures,  it  would 
have  two  bars  per  slot,  which  might  be  arranged  one  over 
the  other  or  side  by  side.  It  is  interesting  to  note  that  each 
slot  would  contain  one  bar  of  each  of  two  windings,  two 
bars  of  the  same  winding  never  occupying  the  same  slot. 

All  the  remarks  regarding  the  winding  of  Fig.  119  apply 
equally  well  to  Fig.  120. 


254  AKMATUKE    WINDINGS   OF   ELECTRIC   MACHINES.  [CHAP.  xv. 


Figure  121  is  a  three-phase  coil  winding,  with  two  groups 
of  conductors  per  pole  piece  per  phase.  The  mechanical 
arrangement  of  the  coils  at  the  ends  of  the  armature  could 
not  be  designed  nearly  so  satisfactorily  from  a  mechanical 
point  of  view,  as  in  the  style  of  winding  given  in  Fig.  123. 
It  is  believed  that  in  most  instances  the  style  of  winding 
shown  in  Fig.  123  will  be  found  to  give  the  best  results. 


Fig.  1  22 


CHAP,  xv.]  THKEE-PHASE   WINDINGS.  257 


Figure  122  is  the  bar  winding  corresponding  to  Fig.  121. 
The  end  connections  are  perfectly  symmetrical  and  well  dis- 
tributed at  one  end,  but  are  far  from  it  at  the  other.  Its 
point  of  superiority  over  Fig.  124  is  that  it  has,  as  a  rule,  no 
great  differences  of  potential  between  adjacent  conductors. 

As  already  stated,  the  irregular  distribution  of  the  end 
conductors  is  not,  at  least  in  the  case  of  bar  windings,  so 
great  an  objection  in  cases  where  there  are  comparatively 
few  bars  per  pole  piece.  And  in  this  instance  there  is  a  sort 
of  a  regularity  about  their  grouping,  that  might  be  found  of 
advantage  on  account  of  the  large  spaces  that  it  makes  avail- 
able for  mechanical  arrangements. 


258  AKMATURE   WINDINGS   OF   ELECTEIC   MACHINES.  [CHAP.  xv. 


Figure  123,  which  was  devised  by  Mr.  Thorburn  Reid, 
who  has  devised  a  number  of  useful  windings,  is  superior  in 
the  mechanical  arrangement  of  the  coils,  to  the  winding  of 
Fig.  121.  The  corresponding  bar  winding  is  not  drawn,  but 
it  may  be  readily  seen  that  it  would  have  no  very  obvious 
advantages. 

Coil  windings  of  the  same  style  as  that  of  Fig.  123  may 
be  constructed  with  any  number  of  coils  per  pole  piece  per 
phase,  and  are  frequently  superior  to  other  arrangements. 

It  is  thought  that  the  style  of  lining  adopted  in  the 
diagram  will  indicate  fairly  well  the  arrangement  of  the  end 
connections,  if  care  is  taken  to  note  that  the  conductors  of 
some  groups  of  coils  are  carried  directly  over  in  the  same 
plane  as  the  face  wires,  to  the  conductors  forming  the  other 

0 

side  of  the  group.  The  end  conductors  of  the  other  coils 
have  to  be  bent  down  out  of  the  plane  of  the  face  conductors 
and  then  back  again  into  their  plane.  The  coils  are  usually 
wound  in  forms  and  then  laid  in  place  on  the  armature. 


Fig".  1  23 


- — ^ 


""*• 


f — •< — ^'  \ 


V 


V 


7\ 


Fig.  1  24 


CHAP,  xv.]  THREE-PHASE   WINDINGS.  261 


Figure  124  is  a  three-phase  bar  winding,  with  two  bars 
per  pole  piece  per  phase.  It  is  perfectly  symmetrical,  and 
may  have  either  one  or  two  conductors  per  group.  It  is 
inferior  to  Fig.  122,  in  that,  from  the  nature  of  the  winding, 
there  are  much  greater  differences  of  potential  between 
adjacent  conductors  than  in  Fig.  122. 

In  Fig.  124,  the  pitch  is  5  at  one  end  and  7  at  the 
other.  Two  sets  of  conductors,  each  set  having  as  many 
conductors  as  there  are  pole  pieces,  are  joined  in  series  to 
form  each  one  of  the  three  windings.  If  an  armature  for 
half  the  voltage  had  been  wished,  the  two  sets  of  con- 
ductors forming  each  winding  would  have  been  connected 
in  parallel. 

This  winding,  as  well  as  the  next  (Fig.  125),  is  of  the 
same  general  character  as  those  shown  in  Figs.  109  and  113. 


262  ARMATUKE   WINDINGS  OF  ELECTRIC  MACHINES.  [CHAP.  xv. 


Figure  125  is  similar  in  all  respects  to  Fig.  124,  except 
that  it  has  three  conductors  per  pole  piece  per  phase.  The 
pitch  is  9  at  both  ends.  It  could  be  connected  so  as  to 
give  one-third  as  great  a  terminal  electromotive  force  by 
joining  the  three  elementary  groups  of  which  each  winding 
is  formed,  in  parallel,  instead  of  in  series. 

In  connection  with  Figs.  124  and  125,  emphasis  should 
be  laid  on  the  fact  that  in  virtue  of  the  nature  of  these  wind- 
ings, whereby  adjacent  conductors  have  between  them  large 
differences  of  potential,  valuable  space  has  to  be  sacrificed 
to  make  room  for  the  proper  thickness  of  insulation,  which, 
with  types  of  winding  not  possessing  this  character,  could 
be  usefully  employed. 


Fig.  1  25 


-«W*i 


VHIVIESIT7] 


Fig.  126 


CHAP,  xv.]  THREE-PHASE   WINDINGS.  265 


Figure  126  is  a  four-pole,  three-phase  bar  winding  of  a  very  irregular 
character.  It  has  fifty-one  conductors,  seventeen  per  phase.  There  are, 
therefore,  unequal  numbers  of  conductors,  both  per  phase  and  per  pole, 
opposite  the  different  pole  pieces. 

This  style  of  winding  has  been  used  with  success  in  induction  motors, 
where  it  is  important  to  choose  a  number  of  slots  on  the  armature,  which  is 
prime,  or  nearly  so,  to  the  number  of  slots  on  the  field.  It  may  be  well  to 
state  that,  in  the  case  of  induction  motors,  the  field,  in  the  most  success- 
ful types,  consists  merely  of  an  assembly  of  annular  punchings  with  radial 
slots  within  which  the  cylindrical  drum  armature  revolves.  It  is  practically 
a  transformer,  one  of  the  elements,  usually  the  secondary,  being  movable. 
It  has  become  customary  to  call  the  moving  element,  the  armature,  and  the 
stationary,  the  field.  In  the  types,  and  for  the  voltages  generally  employed, 
it  has  been  found  best  to  use  a  coil  winding  for  the  field,  the  coils  often 
being  wound  on  forms  and  slipped  into  the  slots.  In  the  armature,  which  is 
practically  a  short-circuited  secondary,  the  number  of  conductors  and  slots 
is  determined  by  the  permissible  inductance,  the  actual  voltage  of  the  arma- 
ture being  to  a  great  extent  immaterial.  In  certain  types  the  ratio  of  field 
to  armature  conductors  has  been  something  like  6:1.  It  is  in  connection 
with  such  motors  as  these,  that  the  winding  diagram  of  Fig.  126  will  be 
found  of  greatest  service.  There  cannot  well  be  more  than  one  bar  per  slot, 
because  of  the  irregularity  of  the  end  connections. 


WITBRSIT7 


266  ARMATURE  WINDINGS  OF  ELECTRIC  MACHINES.  [CHAP.  xv. 


Figure  127  is  another  three-phase  bar  winding  with  fifty- 
one  conductors.  It  has  six  poles,  and  is  even  more  irregular 
than  the  winding  of  Fig.  126.  It,  like  Fig.  126,  will  find 
its  chief  use  in  the  design  of  induction  apparatus.  Wind- 
ings, almost  as  irregular,  might  be  used  in  large  polyphase 
generators,  where  it  is  desired  to  have  but  one  conductor 
per  slot. 


Fig.  1  27 


CHAP,  xv.]  TWO-CIBCUIT   WINDING   FOR  COMMUTATING   MACHINE.  209 


TWO-CIRCUIT  WINDING  FOR  THREE-PHASE  CONTINUOUS- 
CURRENT,  COMMUTATING  MACHINE. 

Figure  128  represents  the  same  winding  as  Fig.  114, 
except  that  here  it  is  tapped  off  at  three  nearly  equidistant 
points  instead  of  at  four,  as  was  the  case  in  Fig.  114. 

The  result  is  a  winding  for  a  three-phase,  continuous- 
current,  commutating  machine. 

The  total  sixty-eight  bars  are  divided  up  into  sets  of 
twenty -two,  twenty-two,  and  twenty-four  conductors,  respect- 
ively, which  are  represented  on  the  diagram  by  heavy,  light, 
and  dotted  lines. 

If  the  conductors  are  arranged  in  groups  of  two  each,  as 
would  frequently  be  the  case  in  projection  armatures,  where 
two  conductors  would  often  be  placed  together  in  each  slot, 
it  is  of  interest  to  note  that  these  two  conductors  never 
belong  to  the  same  phase. 


270 


ABMATUKE   WINDINGS   OF  ELECTRIC   MACHINES. 


1_CHA1'.   XV. 


SIX-CIRCUIT  WINDING  FOR  THREE-PHASE,  CONTINUOUS-CURRENT, 
COMMUTATING  MACHINE. 

Figure  129  is  still  another  three-phase,  continuous-current,  commutating  machine,  but 
with  a  six-circuit  winding.  It  requires  three  leads  per  pair  of  poles  ;  therefore,  in  this 
case,  nine  leads.  It  is  quite  analogous  to  the  quarter-phase,  continuous-current,  corn- 
mutating  machine  of  Fig.  115. 


It  is  of  interest  to  notice  the  relation  of  the  voltage  between  collector  rings  to  the  con- 
tinuous-current voltage  at  the  commutator,  in  the  case  of  three-phase,  continuous-current, 
commutating  machines.  It  will  have  been  observed  that  they  have  "delta"  connected 
windings. 

Let  V=  continuous-current  voltage  at  the  commutator  ;  then,  taking  the  point  of  zero 
potential  to  be  at  the  middle  of  the  winding,  the  electromotive  force  of  each  half  of  the 

winding  is  — .     But  the  corresponding  effective  alternating  electromotive  force  will  be 

SB 

f-r 

This,   therefore,  will   correspond   to  the  voltage   between   common   connection 


2  V2 


(point  of  zero  potential),  and  collector  ring,  for  an  equivalent 
"  Y  "  connected  three-phase  armature  winding.  Now  the 
voltage  between  the  collector  rings  of  the  "  delta  "  connected 
armature  winding  will  be  V3  times  as  great  as  the  voltage 
to  the  common  connection  of  this  equivalent  "  Y  "  winding, 
therefore  the  voltage  between  the  collector  rings  will  be,  — 


2  V2 


where  V=  continuous-current  voltage  at  commutator. 

Inasmuch  as  a  "  delta  "  connected  winding  cannot  be  readily  conceived  to  have  a  point 
of  zero  potential,  the  above  subterfuge  of  substituting  for  it,  the  equivalent  "  Y  "  connected 
winding,  will  often  be  found  to  facilitate  the  handling  of  three-phase  winding  problems. 
When  doing  so,  the  equivalent  "  Y "  potential  and  the  equivalent  "  Y "  current  may  be 
spoken  of  as  attributes  of  a  "delta"  connected  armature.  In  the  accompanying  figure, 
an  equivalent  "  Y  "  connected  winding  is  diagrammatically  shown  dotted  within  a  "  delta  " 
connected  winding. 


Fig.  1  29 


PART  III. 


WINDING  FORMULA   AND   TABLES. 


U5I7BHSITY 


CHAPTER   XVI. 

FORMULAE   FOR   ELECTROMOTIVE   FORCE. 

COMPREHENSIVE  formula  for  the  calculation  of  the  electromotive  force  set  up  in  armatures  may  be 
derived  from  the  formula  for  the  voltage  in  a  circuit,  in  which  the  variation  of  magnetic  flux  is  a  simple 
harmonic  function  of  the  time.  These  formulae  are  :  — 

1.  V=  6.28  TNM  10~s,  the  maximum  voltage  set  up  in  a  cycle  ; 

2.  V=  4.44  TNM  lO'8,  the  effective  voltage  set  up  in  a  cycle ; 

3.  V=  4.00  TNM  10~8,  the  mean  or  average  voltage  set  up  in  a  cycle,v°      ( 

where  V  is  the  voltage  generated,  in  volts  ;  T  the  number  of  turns  in  series,  M  the  number  of  cgs  lines  included 
or  excluded  by  each  of  the  T  turns  in  a  magnetic  cycle,  and  N  the  number  of  magnetic  cycles  per  second. 

In  armatures  of  alternators,  the  effective,  or  square  root  of  the  mean  square  of  the  electromotive  forces  is 
required,  since  this  is  proportional  to  the  effective  voltage,  i.e.  the  voltage  to  maintain  current  O  (square  root 
of  the  mean  square  of  the  current),  in  a  non-inductive  resistance.  In  this  case  it  is  supposed  that  the  T  turns 
are  so  situated  as  to  be  simultaneously  affected  by  any  change  of  the  magnetic  flux,  otherwise  the  voltage  for 
each  of  the  turns  differently  situated  must  be  calculated  separately  and  properly  combined  to  obtain  the 
resultant  voltage. 

In  the  case  of  multi-phase  alternating-current  machines,  the  voltage  in  each  circuit  should  be  calculated, 
and  the  resultant  voltage  derived  according  to  the  method  of  connection,  and  addition  of  vectors  according  to 
the  angle  by  which  the  several  phases  differ  from  each  other. 

In  quarter-phase  machines  with  common  connection,  the  resultant  voltage  is  V5,  or  1.414  times  the 
voltage  generated  in  one  circuit. 

In  three-phase  apparatus,  the  resultant  voltage  is  the  "same  as  the  voltage  generated  in  one  circuit  when 
the  circuits  are  connected  "delta";  and  V3,  or  1.732  times  the  voltage  generated  in  one  circuit  when  the 
circuits  are  connected  "  Y." 

In  alternating-current  commutating  machines,  the  ratio  of  the  voltage  between  the  continuous  and  the, 
alternating  current  circuits  is  1  :  .707  in  the  case  of  single-phase  and  quarter-phase  commutating  machines, 
and  1 :  .612  in  the  case  of  three-phase  commutating  machines.  In  other  words,  if  the  voltage  at  the  con- 

275 


276  ARMATURE   WINDINGS   OF   ELECTRIC   MACHINES.  [CHAP.  xvi. 

tinuous  current  side  is  known,  the  voltage  between  collector  rings  will  be  .707  times  as  great  in  the  case  of 
single  and  quarter  phase  commutating  machines,  and  will  be  .612  times  as  great  in  the  case  of  three-phase 
commutating  machines. 

In  armatures  of  continuous-current  dynamos,  the  voltage  at  the  terminals  is  constant  during  any  period 
considered,  and  is  the  integral  of  all  the  voltages  successively  set  up  in  the  different  armature  coils  according 
to  their  position  in  the  magnetic  field;  and  since  in  this  case  only  average  voltages  are  considered,  the  resultant 
voltage  is  independent  of  any  manner  in  which  the  magnetic  flux  may  vary  through  the  coils. 

Formula  3  is  applicable  to  all  continuous-current  armatures,  whether  ring,  drum  or  disc,  two-circuit  or 
multiple  circuit,  and  whether  the  winding  be  single  or  multiple. 

The  simplicity  and  wide  applicability  of  these  formula;  make  them  preferable  to  many  others  that  are 
difficult  to  interpret,  because  of  the  many  accessory  conditions  that  must  be  kept  in  mind. 

Although,  by  the  constants  given  above,  the  voltages  may  be  obtained  at  the  alternating  current,  as  well 
as  at  the  continuous  current  terminals  of  commutating  machines,  the  former,  i.e.  the  voltages  at  the  alter- 
nating current  terminals,  may  be  obtained  from  the  following  formulae,  in  which  V  is  the  required  voltage 
between  collector  rings,  T  is  the  number  of  turns  in  series  between  collector  rings,  M  is  the  magnetic  flux  from 
one  pole  piece  into  the  armature,  and  N  is  the  number  of  cycles  per  second :  — 

For  single  and  quarter  phase  commutating  machines,  V=  2.83  TNM  10~8. 
For  three-phase  commutating  machines,  V=  3.69  TNMr*. 


CHAPTER   XVII. 

METHOD  OF  APPLYING  THE  ARMATURE  WINDING  TABLES. 

THE  nature  and  use  of  the  tables  may  be  most  easily  understood  by  applying  them  to  the  solution  of  a 
few  examples. 

EXAMPLE  1.  —  If  we  wish  a  two-circuit,  triple  winding  for  a  drum  armature,  with  about  670  con- 
ductors and  six  poles,  what  is  the  exact  number  of  conductors  that  must  be  employed  to  give  us  a  singly  re- 
entrant winding  ? 

Turning  to  page  312,  we  find  that  a  two-circuit,  triple  winding  with  670  conductors,  is  impossible  for 
six  poles,  but  that  672  conductors  may  be  used  ;  and  to  have  the  winding  singly  re-entrant,  the  front  and  back 
pitches  must  each  equal  113.  If  the  front  and  back  pitches  should  be  taken  equal  to  111,  a  triply  re-entrant 
winding  would  result. 

EXAMPLE  2.  —  We  next  wish  to  ascertain  how  many  volts  this  machine  will  give  when  the  armature  is 
driven  at  440  r.p.m.,  if  the  flux  from  each  pole  piece  into  the  armature  equals  2.25  megalines. 

The  table  of  Drum  Winding  Constants  on  page  280  tells  us  that  with  100  conductors,  100  r.p.m., 
and  a  flux  equal  to  one  megaline,  the  terminal  volts  will,  for  a  six-pole  machine,  be  equal  to  1.667.  Therefore, 
in  the  case  before  us,  we  have 

F=1.667  x  6.72  x  4.40  x  2.25  =  111  volts. 

From  the  same  table  we  find  that  for  a  two-circuit,  triple  winding  with  six  poles,  we  have  .200  aver- 
age volts  between  commutator  segments  per  megaline  and  per  100  r.p.m.  So,  in  this  case,  we  shall  have 
.200x2.25x4.40  =  1.98  average  volts  between  commutator  segments. 

EXAMPLE  3.  — Certain  conditions  fix  the  flux  of  a  dynamo  from  one  pole  piece  into  the  armature  at  8.30 
megalines,  and  the  speed  at  100  r.p.m.  If  we  wish  to  employ  an  eight-pole,  two-circuit,  double  winding,  how 
many  conductors  do  we  need,  to  obtain  150  volts  ? 

Consulting  the  table  of  Drum  Winding  Constants,  on  page  280,  we  find  that  for  eight-pole,  two-circuit, 
double  windings,  we  have  3.33  volts  per  100  conductors  with  100  r.p.m.,  and  one  megaline  of  flux.  Therefore, 

we  shall  require  — —  x—  —=544  conductors. 

By  reference  to  page  301,  it  will  be  seen  that  for  eight  poles,  the  nearest  number  of  conductors  that 
we  can  use  in  order  to  have  a  two-circuit,  double  winding,  is  540  or  548.  Suppose  we  use  540  conductors.  If 
we  wish  a  doubly  re-entrant  winding,  we  shall  take  the  pitch  at  one  end  equal  to  67,  and  that  at  the  other  end 
equal  to  69. 

EXAMPLE  4.  —  A  slotted  armature  is  to  have  ten  poles,  and  a  two-circuit,  triple  winding,  with  eight 
conductors  per  slot. 

277 


278  AEMATURE   WINDINGS   OF   ELECTRIC   MACHINES.  [CHAP.  xvn. 

By  reference  to  the  table  of  Summarized  Conditions  for  Two-Circuit,  Triple  Windings,  on  page  283,  we 
find  that  it  may  be  either  singly  or  triply  re-entrant,  according  to  the  number  of  conductors  used. 

The  winding  is  to  have  424  conductors.  Turning  to  page  310,  it  is  seen  that  the  pitch  must  be  43  at 
both  ends,  and  that  for  424  conductors  the  winding  must  be  singly  re-entrant. 

If  the  flux  is  20.0  megalines,  and  the  speed  105  r.p.m.,  we  find  from  page  280  that  the  voltage  will  be 

2.78x4.24x1.05x20.0  =  247  volts. 
The  average  volts  per  bar  are 

.556x20.0x1.05  =  11.7  volts. 

EXAMPLE  5. — An  eight-pole  armature  has  a  multiple-circuit,  double  winding,  with  1258  conductors. 
By  consulting  page  343,  we  find  that  it  is  singly  re-entrant,  and  that  the  pitch  should  be  155  at  one  end,  and 
159  at  the  other.  It  is,  of  course,  understood  that  these  pitches  are  taken  in  opposite  directions.  One  of 
them  might  have  been  indicated  as  positive,  and  the  other  as  negative.  It  may  be  well  to  point  out  here 
that  the  letters  F  and  B  at  the  head  of  the  tables,  meaning  respectively,  "  front "  and  "  back,"  are  interchange- 
able, meaning  merely  that  the  one  figure  represents  the  pitch  at  one  end,  and  the  other  figure,  that  at  the 
other  end.  This  is  true  in  regard  to  all  the  tables,  both  two-circuit  and  multiple-circuit. 

Returning  to  Example  5,  the  voltage  of  the  machine,  assuming  the  flux  equals  7.85  megalines,  and  a  speed 
of  300  r.p.m.,  is  found  by  the  table  of  Drum  Winding  Constants  on  page  280,  to  be 

.  833  x  12. 58  x  3. 00  x  7 ,85  =  247  volts. 

The  average  volts  per  bar  are 

.1333  x  7.85  x  3.00  =  3.14  volts. 

EXAMPLE  6.  —  A  two-circuit,  single  winding  is  wanted,  with  four  conductors  per  slot. 

From  the  table  of  Summarized  Conditions  for  Two-Circuit,  Single  Windings,  on  page  281,  it  may  be  seen 
that  this  is  only  possible  with  6, 10, 14,  etc.,  poles  ;  being  impossible  with  4,  8, 12, 16,  etc.,  poles.  The  winding 
is  designed  for  fourteen  poles,  and  660  conductors.  We  find  from  page  329,  that  the  pitch  is  47  at  both  ends. 
The  machine  gives  160  volts,  and  the  speed  is  75  r.p.m.  By  the  aid  of  the  table  on  page  280,  we  find  that 
the  flux  is  equal  to 

JnjTJf^  =  2.77  megaline, 

Average  volts  per  commutator  segment  =  3.27  x  2.77  x  .75=6.80  volts. 

The  above  examples  have  all  been  chosen  merely  to  illustrate  the  use  of  the  tables,  and  the  relative 
magnitudes  employed  in  any  one  example  are  not  such  as  would  occur  in  practice. 

The  tables  on  pages  280,  281,  282,  and  283  are  constructed  on  the  assumption  that  no  interpolated  com- 
mutator segments  are  employed,  and  that  no  portion  of  the  normal  number  of  commutator  segments  is 
omitted,  and  when  this  is  not  the  case,  the  results  should  be  properly  modified,  as  may  readily  be  done. 

In  all  the  tables,  a  proper  interpretation  of  the  term  "  conductors "  should  be  made.  As  stated  in  the 
introductory  chapter,  "  groups  of  conductors  "  may  often  be  substituted  therefor. 

It  is  believed  that  after  becoming  familiar  with  the  arrangement  of  the  tables,  their  use  will  be  found  to 
be  of  value  in  a  great  variety  of  problems  connected  with  armature  windings.  Any  single  result  can,  however, 
be  obtained  by  an  application  of  the  rules  and  formulae  given  in  the  text,  but  after  these  rules  and  formulae  are 
once  understood,  it  will  be  found  that  subsequent  problems  will  generally  be  most  conveniently  solved  by 
means  of  the  tables. 


CHAPTER  XVIII. 

ARMATURE   WINDING   TABLES. 


DRUM  WINDING  CONSTANTS. 


NUMBER  OF  POLES 

CLASS  OF  WINDING. 

4 

6 

8 

10 

12 

14 

16 

DRUM  ARMATURES. 

VOLTS  PER  100  CONDUCTORS 
PER  100  R.  P.  M.  AND 
FLUX-ONE  MEGALINE. 

3     H 

Single 

1.667 

1.667 

1.667 

1.667 

1.667 

1.667 

1.667 

Eb    ID 

1-      0 

-i    <r 

i  5 

Double 

.833 

.833 

.833 

.833 

.833 

.833 

.833 

Triple 

.556 

.556 

.556 

.556 

.556 

.656 

.556 

TWO 
CIRCUIT 

Single 

3.33 

5.00 

6.67 

8.33 

10.00 

11.67 

13.33 

Double 

1.667 

2.50 

3.33 

4.17 

5.00 

5.83 

6.67 

Triple 

1.111 

1.667 

2.22 

2.78 

3.33 

3.89 

1.41 

AVERAGE 
VOLTS  BETWEEN  COMMUTA- 
TOR SEGMENTS  PER  MEGA 
LINE  &  PER  100  R.  P.  M. 
(INDEPENDENT  OF  NO.  OF  CON.DS.) 

MULTIPLE 
CIRCUIT 

Single 

.1333 

.200 

.267 

.333 

.400 

.467 

.533 

Double            ® 

.0668 

.100 

.1333 

.1667 

.200 

.233 

.267 

Triple              ® 

.0115 

.0667 

.0888 

.1111 

.1333 

.1555 

.1778 

TWO 
CIRCUIT 

Single 

.267 

.c,oo 

1.068 

1.668 

2.40 

3.27 

4.27 

Double            Q2 

.1333 

.300 

.534 

.834 

1.200 

1.  <;:;.-> 

2.14 

Triple              ® 

.0888 

.200 

.356 

.556 

.800 

1.09 

1.42 

©  With  Multiple  Windings,  the  maximum  Volts  per  bar  is  much  more  greatly  in  excess  of  the  average  Volts  per  bar  than  in  Single 
Windings.  This  may  be  seen  by  a  careful  analysis  of  such  Windings;  which  also  shows  that  this  may  be  more  or  less  overcome  by  care- 
fuLmutual  adjustment  of  the  position  of  the  Brushes.  This  would  not,  however,  be  practicable  with  present  methods. 


DATA  FOR  APPLYING  TWO-CIRCUIT,  SINGLE  WINDINGS, 
FOR  DRUM  ARMATURES. 

o  o  3U 
2^-5 
c  ^  i  < 

UCL  h-g 

**» 

w  $  2?  °» 

2  i-  o  u  ^ 

giiBs* 

5§5S| 

—  I    2    UJ    ^ 

O  0  2 
>   0  2 

NUMBER  OF 
POLES 

CONDUCTORS  PER  SLOT 

^O)  >  w 

mx-f-s 

5g»r 

°§a:  II 

>"(r 

4 

1 

2 

6 

10 

14 

3.33 

.267 

6 

1 

2 

4 

8 

10 

14 

16 

5.00 

.600 

8 

1 

2 

6 

10 

14 

6.67 

1.068 

10 

1 

2 

4 

6 

8 

12 

14 

16 

8.33 

1.668 

12 

1 

2 

10 

14 

1000 

2.40 

14 

1 

2 

4 

6 

8 

10 

12 

16 

11.67 

3.27 

16 

1 

2 

6 

10 

14 

13.33 

4.27 

Q)  Independent  of  number  of  Conductors 

From  the  above  Table  the  following  Rule  may  be  deduced: 

In  the  ordinary  two-circuit  single  winding,  "C"  is  always  such  a  number  that  the  number  of  conductors  per  slot,  and  "n"  the  number 
of  poles,  cannot  have  a  common  factor  greater  than  2. 


UFJ7BRSIT7 


DATA  FOR  APPLYING  TWO-CIRCUIT,  DOUBLE  WINDINGS, 
FOR  DRUM  ARMATURES. 

iff! 

0-  liJ  X  < 
UJ  tt-  H  0 

Pis 

w  °-  S;     . 
u  §   oi  <|  2 

mii« 

5f«38 

;;  2  uj  — 
§    0   2 
>  o 

NUMBER  OF 
POLES 

CONDUCTORS  PER  SLOT 

0.      .  -  ui 
cn££s 

bgar 

>§^" 

1 

2 

4 

6 

8 

10 

12 

14 

16 

4 

(3D  • 
oo 

(3D 
oo 

<3D 

oo 

(3D 

00 

CD 

(3D 

00 

CD 

00 

00 

oo 

G) 

1.667 

.1333 

6 

<3D 
o  o 

00 

00 

00 

OO 

(3D 
o  o 

(3D 

0  0 

00 

2.50 

300 

8 

(3D 
oo 

© 

o  o 

(3D 
o  o 

<33 

00 

(5) 

00 

C5D 
oo 

OD 

00 

3.33 

.534 

10 

(3D 
o  o 

(3D 
o  o 

OO 

(3D 
o  o 

00 

oo 

(3D 
o  o 

OO 

4.17 

.834 

12 

(5) 
o  o 

(3D 
o  o 

(3D 

00 

© 

CD 

00 

(3D 
oo 

© 

5.00 

1.200 

14 

GO 

o  o 

(3D 

00 

00 

(3D 

00 

oo 

(3D 
oo 

oo 

00 

5.83 

1.635 

16 

(3D 

0  0 

O 

00 

(3D 
oo 

(3D 
oo 

(3D 
oo 

(3D 
oo 

C5D 

00 

6.67 

2.14 

©  Independent  of  number  of  Conductors 

©  Moreover,  in  multiple  Windings  this  value  is  merely  nominal,  as  a  careful  analysis  of  Multiple  Windings  shows  that  if  this  value 
can  be  approached  at  all,  it  is  only  by  means  of  more  careful  mutual  adjustment  of  the  Brushes  than  is  practicable  with  present  methods. 


DATA  FOR  APPLYING  TWO-CIRCUIT,  TRIPLE  WINDINGS, 
FOR  DRUM  ARMATURES. 

VOLTS  PER  100 
CONORS.  PER  100 
R.P.M.  WITH  FLUX 
=     1  MEGALINE 

AVERAGE 
VOLTS  BETWEEN 
COMMR.  SEGTS. 
PER  MEGALINE& 
PERIOD  R.  P.  M. 
® 

NUMBER 
OF  POLES 

CONDUCTORS  PER  SLOT 

1 

2 

4 

6 

8 

10 

12 

14 

16 

4 

(as) 

ooo 

(22) 
ooo 

OOO 

(22) 

000 

(22) 

000 

1.111 

.0888 

6 

(22) 

000 

(22) 
ooo 

(22) 
ooo 

(22) 

000 

(20) 
ooo 

@) 

ooo 

(22) 
ooo 

(22) 

000 

(22) 
ooo 

1.6(57 

.200 

8 

d5> 

ooo 

(42) 
ooo 

OOO 

(22) 
ooo 

(22) 

000 

2.22 

.356 

10 

(22) 

000 

(22) 

000 

(22) 

000 

OOO 

ooo 

OOO 

(22) 
ooo 

(22) 

000 

2.78 

.556 

12 

(22) 

ooo 

(22) 
ooo 

<SD 

000 

(22) 
ooo 

(2ft) 

000 

3.33 

.800 

14 

(22) 

000 

(2ft) 

ooo 

(22) 

ooo 

OOO 

(22) 
ooo 

(22) 

000 

ooo 

(22) 
ooo 

3.89 

1.09 

16 

<S> 

ooo 

(22) 

000 

OOO 

(22) 

ooo 

(2ft) 
ooo 

4.44 

1.42 

®    Independent  of  number  of  Conductors 

@  Moreover,  in  Multiple  Windings  this  value  is  merely  nominal,  as  a  careful  analysis  of  Multiple  Windings  shows  that  if  this  value 
can  be  approached  at  all,  it  is  only  by  means  of  more  careful  mutual  adjustment  of  the  Brushes  than  is  practicable  with  present  methods. 


WINDING  TABLES   FOR  TWO^CIRCUIT,   SINGLE   WINDINGS 

FOR   DRUM  ARMATURES. 


TABLE  OF  TWO-CIRCUIT,  SINGLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

No.  OF  CONDUCTORS 

4 
POLES 

6 
POLES 

8 

POLES 

10 
POLES 

12 
POLES 

14 
POLES 

16 
POLES 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

102 

l& 

25 

•2J 
27 

13 

13 

9 

11 

102 

104 

17 

17 

104 

106 

| 

27 
27 

17 

19 

13 

13 

9 

9 

106 

108 

11 

11 

108 

110 

27 
27 

27 
29 

17 

19 

13 

15 

9 

9 

7 

9 

7 

7 

110 

112 

19 

19 

11 

11 

112 

114 

27 

29 

29 
29 

13 

15 

7 

9 

7 

7 

114 

116 

19 

19 

116 

118 

20 
29 

29 
31 

19 

21 

15 

15 

11 

13 

9 

11 

118 

120 

120 

122 

B 

31 

81 
31 

19 

21 

15 

15 

11 

13 

9 

11 

122 

124 

•Jl 

21 

9 

9 

12i 

126 

31 
31 

81 
33 

15 

17 

7 

9 

126 

128 

21 

21 

13 

13 

9 

9 

128 

130 

31 
33 

33 
33 

21 

23 

15 

17 

11 

11 

7 

9 

130 

132 

13 

13 

132 

134 

a:-: 
33 

33 
35 

21 

23 

17 

17 

11 

11 

134 

136 

23 

23 

136 

138 

as 

35 

B 

35 

17 

17 

13 

15 

9 

11 

138 

140 

28 

23 

140 

142 

JD 

35 

i 

28 

25 

17 

19 

13 

15 

11 

13 

9 

11 

9 

9 

142 

144 

144 

146 

35 
87 

37 
37 

23 

25 

17 

19 

11 

13 

9 

9 

146 

148 

25 

25 

15 

15 

148 

150 

87 
37 

87 
39 

19 

19 

150 

152 

25 

25 

.15 

15 

11 

11 

152 

154 

87 
SB 

H 

89 

25 

27 

19 

1!) 

13 

13 

154 

156 

11 

11 

156 

158 

• 
39 

39 

•11 

25 

27 

19 

21 

15 

17 

13 

13 

9 

11 

158 

160 

27 

27 

160 

162 

41 

41 
41 

1!) 

21 

15 

17 

9 

11 

162 

164 

23 

27 

164 

ICG 

41 
41 

41 

4:i 

27 

29 

21 

:'\ 

13 

15 

11 

13 

166 

168 

17 

17 

168 

170 

41 
43 

43 
43 

27 

ill 

21 

21 

13 

15 

11 

13 

170 

172 

2!) 

29 

17 

17 

172 

174 

43 
43 

i 

21 

23 

11 

11 

174 

176 

29 

29 

176 

178 

43 
45 

45 
45 

29 

31 

21 

28 

17 

111 

15 

15 

11 

11 

178 

180 

13 

13 

180 

182 

46 
45 

8 

47 

29 

31 

23 

23 

17 

19 

15 

15 

182 

184 

31 

31 

13 

13 

184 

186 

45 
47 

47 
47 

23 

23 

186 

188 

31 

31 

19 

19 

188 

190 

47 
47 

47 
49 

31 

33 

•2:! 

25 

15 

17 

11 

13 

190 

192 

19 

19 

192 

194 

47 
49 

49 
« 

81 

33 

23 

25 

15 

17 

13 

15 

11 

13 

194 

196 

88 

33 

196 

198 

49 
49 

i 

25 

25 

19 

21 

13 

15 

198 

200 

33 

33 

200 

4 

6 

8 

10 

12 

14 

16 

UNIVERSITY 


TABLE  OF  TWO-CIRCUIT,  SINGLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES. 

No.  OF  CONDUCTORS 

4 

POLES 

6 

POLES 

8 
POLES 

10 

POLES 

12 

POLES 

14 

POLES 

16 
POLES 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

202 

40 
51 

8 

51 

33 

35 

25 

25 

19 

21 

17 

17 

202 

204 

l     204 

206 

61 

51 

51 

58 

33 

35 

25 

27 

17 

17 

13 

13 

206 

208 

35 

35 

21 

21 

15 

15 

208 

210 

61 
68 

• 
&3 

25 

27 

13 

13 

210 

212 

35 

35 

21 

21 

15 

15 

212 

214 

63 
63 

63 
66 

58 

37 

27 

27 

17 

19 

214 

216 

216 

218 

53 
05 

65 
65 

35 

37 

27 

27 

21 

23 

17 

19 

218 

220 

37 

37 

220 

222 

56 

B 

8? 

27 

29 

21 

23 

15 

17 

13 

15 

222 

224 

37 

37 

224 

226 

i 

1 

37 

39 

27 

29 

19 

19 

15 

17 

13 

15 

226 

228 

23 

23 

228 

230 

67 
67 

i 

37 

55 

29 

29 

19 

19 

230 

2:!2 

39 

39 

23 

23 

232 

234 

67 

59 

1 

29 

29 

234 

236 

39 

39 

17 

17 

236 

238 

H 

6» 

I 

39 

41 

29 

31 

23 

25 

19 

21 

15 

15 

238 

240 

17 

17 

240 

242 

69 
61 

| 

39 

41 

29 

31 

23 

25 

19 

21 

15 

15 

242 

244 

41 

41 

244 

246 

01 

01 

61 
63 

31 

31 

240 

218 

41 

41 

25 

25 

248 

250 

61 

63 

63 
63 

41 

43 

31 

31 

21 

21 

17 

19 

250 

252 

25 

25 

252 

254 

68 

63 

I 

41 

43 

31 

33 

21 

21 

17 

19 

15 

17 

251 

250 

43 

43 

256 

258 

| 

| 

31 

33 

25 

27 

15 

17 

258 

2(10 

43 

43 

260 

2G2 

| 

66 
«7 

43 

45 

33 

33 

25 

27 

21 

2;! 

262 

2lil 

19 

19 

264 

200 

| 

67 
67 

43 

45 

33 

33 

21 

23 

266 

208 

45 

45 

27 

27 

19 

19 

268 

270 

67 
67 

til 
69 

33 

35 

17 

17 

270 

272 

45 

45 

27 

27 

272 

274 

67 
89 

58 

45 

47 

33 

35 

23 

23 

17 

17 

274 

276 

276 

278 

| 

i 

45 

47 

35 

35 

27 

29 

23 

23 

19 

21 

278 

280 

47 

47 

280 

282 

| 

71 
71 

35 

35 

27 

29 

19 

21 

282 

284 

47 

47 

284 

286 

71 
n 

71 
73 

47 

49 

35 

37 

23 

25 

17 

19 

280 

288 

29 

29 

288 

290 

71 
18 

13 
73 

47 

49 

35 

37 

23 

25 

17 

19 

290 

292 

49 

49 

29 

29 

21 

21 

292 

294 

5 

78 

?! 

37 

37 

294 

296 

49 

49 

21 

21 

296 

298 

• 
7* 

| 

49 

51 

37 

37 

29 

31 

25 

25 

298 

300 

300 

4     ' 

6 

8 

40 

12 

14 

16 

TABLE  OF  TWO-CIRCUIT,  SINGLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

No.OF  CONDUCTORS 

4 

POLES 

6 
POLES 

8 

POLES 

10 
POLES 

12 

POLES 

14 

POLES 

16 

POLES 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

302 

75 

77 

49 

51 

37 

39 

29 

31 

25 

25 

19 

19 

302 

304: 

51 

51 

304 

306 

7T 
II 

37 

39 

21 

23 

19 

19 

306 

308 

51 

51 

31 

31 

308 

310 

77 

71 
79 

51 

53 

39 

39 

25 

•11 

21 

23 

310 

31'2 

31 

31 

3ll> 

314 

71 
79 

19 
7U 

51 

53 

89 

39 

25 

27 

314 

316 

53 

53 

316 

318 

19 

7U 

79 
81 

39 

41 

31 

33 

19 

21 

318 

320 

53 

53 

23 

23 

320 

322 

71) 

si 

Bl 
81 

53 

55 

39 

41 

31 

33 

27 

27 

19 

21 

322 

324 

23 

23 

324 

326 

si 

81 

81 
83 

53 

55 

41 

41 

27 

27 

326 

328 

55 

55 

33 

33 

328 

330 

81 
83 

B 

83 

41 

41 

330 

332 

55 

55 

33 

33 

332 

334 

if 

83 

S5 

55 

57 

41 

43 

27 

29 

23 

25 

21 

21 

334 

336 

336 

338 

83 
86 

85 

86 

55 

57 

41 

43 

33 

35 

27 

29 

23 

25 

21 

21 

338 

340 

57 

57 

310 

342 

85 

86 

tf5 
gj 

43 

43 

33 

35 

342 

344 

57 

57 

344 

346 

85 

87 

87 
87 

57 

59 

43 

43 

29 

29 

346 

348 

35 

35 

25 

25 

348 

350 

87 
87 

87 

§ 

57 

69 

43 

45 

29 

29 

•2\ 

23 

350 

352 

59 

59 

35 

35 

25 

25 

352 

354 

87 
89 

89 
89 

43 

45 

•21 

23 

354 

356 

59 

59 

356 

358 

89 

89 

89 
Ul 

655 

61 

45 

45 

35 

37 

29 

31 

358 

360 

360 

362 

t!'J 
91 

'.'1 
111 

59 

61 

45 

45 

35 

37 

29 

31 

25 

27 

362 

364 

61 

61 

364 

366 

91 

93 

45 

47 

25 

27 

23 

23 

3i;i; 

368 

.61 

61 

37 

37 

368 

370 

n 

03 

93 
g 

61 

63 

46 

47 

31 

31 

23 

23 

370 

372 

37 

37 

372 

374 

93 

8 

61 

03 

47 

47 

31 

31 

374 

376 

68 

63 

27 

27 

376 

378 

93 
95 

ui 
'.'."i 

47 

47 

37 

39 

378 

380 

63 

63 

27 

27 

380 

382 

05 

9u 
97 

63 

65 

47 

49 

37 

39 

31 

33 

23 

25 

382 

384 

384 

386 

95 
97 

97 
07 

63 

65 

47 

49 

31 

33 

23 

25 

386 

388 

65 

65 

39 

39 

388 

390 

97 
97 

n 

99 

49 

49 

27 

29 

390 

392 

65 

65 

39 

39 

392 

394 

<J7 
99 

99 
99 

65 

67 

49 

49 

33 

33 

27 

29 

394 

396 

396 

398 

99 
99 

99 

K'l  .    .. 

65 

67 

49 

51 

39 

41 

33 

33 

25 

25 

398 

400 

67 

67 

400 

4 

6 

8 

10 

12 

14 

16 

TABLE  OF  TWO-CIRCUIT,  SINGLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

CO 

tc 

o 

4 

POLES 

6 

POLES 

8 

POLES 

10 

POLES 

12 

POLES 

14 

POLES 

16 

POLES 

o 

3 
o 
z 
o 
o 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

o 

6 

Z 

402 

• 

101 

}• 
01, 

49 

51 

39 

41 

25 

25 

402 

404 

67 

67 

ii'j 

29 

404 

406 

101 
101 

101 
.103 

67 

69 

51 

51 

33 

35 

406 

408 

41 

41 

29 

29 

408 

110 

161 
103 

Ida 

103 

67 

69 

51 

51 

33 

35 

410 

412 

69 

69 

41 

41 

412 

414 

10:1 

103 

i 

51 

53 

25 

27 

414 

416 

69 

69 

416 

418 

103 
105 

106 
105 

69 

71 

51 

53 

41 

43 

35 

35 

29 

31 

25 

27 

418 

420 

4~20 

4*2 

106 

105 

106 
107 

69 

71 

53 

53 

41 

43 

35 

::,-) 

l>9 

:;\ 

422 

l-l 

71 

71 

424 

426 

• 
107 

1U7 
107 

53 

53 

426 

428 

71 

71 

43 

43 

428 

430 

107 
107 

107 
109 

71 

73 

53 

55 

35 

37 

27 

27 

430 

432 

43 

43 

31 

31 

432 

434 

107 
109 

109 
109 

71 

73 

53 

55 

35 

37 

27 

27 

434 

436 

73 

73 

:;i 

31 

436 

4:js 

109 
109 

10« 

in 

5V) 

55 

43 

45 

438 

440 

73 

73 

440 

1  \'2 

109 
111 

111 
in 

7:; 

75 

55 

55 

43 

45 

37 

37 

442 

444 

444 

446 

111 
111 

111 

113 

73 

75 

55 

57 

37 

37 

31 

33 

27 

29 

446 

448 

75 

75 

45 

45 

41  S 

450 

111 
113 

113 
113 

55 

57 

31 

33 

27 

29 

450 

I  .v_> 

75 

75 

45 

45 

452 

454 

113 
113 

113 
115 

75 

77 

57 

57 

37 

39 

454 

456 

456 

458 

113 
115 

116 
115 

75 

77 

57 

57 

45 

47 

37 

.;'.» 

458 

460 

77 

77 

33 

33 

460 

462 

11& 
115 

115 
117 

57 

59 

45 

47 

29 

1><) 

462 

464 

77 

77 

33 

33 

464 

466 

116 
117 

117 

11T 

77 

79 

57 

59 

39 

39 

29 

29 

466 

468 

47 

47 

468 

470 

117 
117 

117 

119 

77 

79 

59 

59 

39 

39 

470 

472 

79 

79 

47 

47 

472 

474 

117 

lift 

11V 

11U 

59 

59 

33 

35 

474 

476 

79 

79 

476 

478 

ll'J 

i:  i 

119 

121 

79 

81 

,VJ 

61 

47 

49 

39 

41 

88 

35 

29 

31 

478 

ISO 

480 

is-J 

121 

121 
121 

79 

81 

59 

61 

47 

•!'.) 

39 

41 

29 

31 

482 

1SI 

81 

81 

484 

IM; 

i:  1 
121 

121 

123 

61 

61 

486 

488 

SI 

81 

49 

49 

35 

35 

488 

490 

121 
123 

123 
123 

81 

83 

61 

61 

II 

41 

490 

I!I2 

49 

49 

35 

35 

492 

I'.M 

123 
123 

123 
125 

81 

83 

61 

63 

41 

41 

31 

31 

494 

496 

83 

83 

496 

498 

B 

125 

i:  • 
125 

61 

63 

49 

51 

31 

31 

4S)8 

500 

83 

83 

500 

4 

6 

8 

10 

12 

14 

16 

TABLE  OF  TWO  CIRCUIT,  SINGLE  WINDINGS,  FOR  DRUM  ARMATURES. 

CO 
(E 
O 
l~ 

FRONT  AND  BACK  PITCHES 

No.  OFCONDUCTORS 

rCONDUC 

4 

POLES 

6 
POLES 

8 
POLES 

10 

POLES 

12 

POLES 

14 

POLES 

16 

POLES 

O 

6 

z 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

502 

1-J5 

m 

125 
Ifi 

83 

85 

63 

63 

49 

51 

41 

43 

35 

37 

502 

504 

504 

506 

IB 

127 

127 

83 

85 

63 

63 

41 

43 

35 

37 

506 

508 

85 

85 

51 

51 

508 

510 

127 
Hi? 

127 

120 

63 

65 

31 

33 

510 

512 

85 

85 

51 

51 

512 

514 

uv 

1-J'J 

lay 

129 

85 

87 

63 

65 

43 

43 

31 

33 

514 

516 

37 

37 

516 

518 

in 

12'J 

ui 

85 

87 

.    65 

65 

51 

53 

43 

43 

518 

520 

87 

87 

37 

37 

520 

522 

iiiu 
m 

23 

65 

65 

51 

53 

522 

524 

87 

87 

524 

526 

j3i  . 
ui 

{33 

87 

89 

65 

67 

43 

45 

33 

33 

526 

528 

53 

53 

528 

530 

IB 

133 

133 
133 

87 

89 

65 

67 

43 

45 

37 

39 

33 

33 

530 

532 

89 

89 

53 

53 

532 

534 

133 
133 

1311 
135 

67 

67 

37 

39 

534 

536 

89 

89 

536 

538 

136 

13 

135 

89 

ill 

67 

67 

53 

55 

45 

45 

538 

540 

540 

542 

136 
135 

135 

137 

89 

91 

67 

69 

53 

55 

45 

45 

33 

35 

542 

544 

91 

91 

39 

39 

544 

546 

137 

137 
13' 

67 

69 

33 

35 

546 

548 

91 

91 

55 

55 

39 

39 

548 

550 

137 
13T 

137 
1311 

91 

m 

69 

69 

45 

47 

550 

552 

55 

55 

552 

554 

137 
131* 

139 
>38 

91 

93 

69 

69 

45 

47 

554 

556 

93 

93 

556 

558 

UB 

13<J 

139 
HI 

69 

71 

55 

57 

39 

41 

35 

35 

558 

560 

93 

93 

560 

562 

lay 
HI 

111 

93 

95 

69 

71 

55 

57 

47 

47 

39 

41 

35 

35 

562 

564 

564 

566 

11! 

a 

93 

95 

71 

71 

47 

47 

566 

568 

95 

95 

57 

57 

568 

570 

HI 
U3 

143 
143 

71 

71 

570 

572 

95 

95 

57 

67 

41 

41 

572 

574 

141 

u:; 

143 
145 

95 

97 

71 

73 

47 

49 

35 

37 

574 

576 

41 

41 

576 

578 

143 
1« 

145 
U5 

95 

97 

71 

73 

57 

59 

47 

49 

35 

37 

878 

580 

97 

97 

580 

582 

1-}:. 
145 

14o 
147 

73 

73 

57 

59 

582 

584 

97 

97 

584 

586 

145 
147 

147 
147 

97 

99 

73 

73 

49 

49 

41 

43 

586 

588 

59 

59 

588 

,_590 

147 
147 

147 
149 

97 

99 

73 

75 

49 

49 

4] 

43 

37 

37 

590 

592 

99 

99 

59 

59 

592 

594 

a 

149 

73 

70 

37 

37 

594 

59(> 

99 

99 

59C, 

598 

i 

151 

99 

101 

75 

75 

59 

61 

49 

51 

51)8 

600 

43 

43 

600 

4 

6 

8 

10 

12 

14 

16 

TABLE  OF  TWO  CIRCUIT  SINGLE  WINDINGS  FOR  DRUM  ARMATURES. 

No.  Of  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

No.  OF  CONDUCTORS 

4 

POLES 

6 

POLES 

8 
POLES 

10 
POLES 

12 

POLES 

14 

POLES 

16 

POLES 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

602 

149 

161 

161 
151 

99 

101 

75 

75 

59 

61 

49 

51 

002 

604 

101 

101 

43 

43 

604 

606 

ill 

161 
163 

75 

77 

37 

39 

606 

608 

101 

101 

61 

61 

608 

610 

IB 

l&S 

1W 
163 

101 

103 

75 

77 

51 

51 

37 

39 

010 

612 

61 

61 

612 

OM 

I.--: 
163 

B 

166 

101 

103 

77 

77 

51 

51 

43 

45 

6U 

jiir, 

103 

103 

616 

618 

163 
165 

155 
166 

77 

77 

61 

63 

43 

45 

018 

620 

103 

103 

620 

622 

165 

155 

165 
167 

103 

105 

77 

79 

61 

63 

51 

53 

39 

39 

0-22 

624 

024 

626 

{• 

167 

167 

157 

103 

105 

77 

79 

51 

53 

39 

39 

026 

628 

105 

105 

63 

63 

45 

45 

628 

630 

167 
167 

157 
151) 

79 

79 

630 

632 

105 

105 

63 

63 

45 

45 

(532 

634 

157 
168 

15» 

105 

107 

79 

79 

53 

53 

634 

636 

636 

638 

m 

16» 

! 

105 

107 

79 

81 

63 

65 

53 

53 

39 

41 

638 

010 

107 

107 

040 

642 

16» 
101 

01 
01 

79 

81 

63 

65 

45 

47 

39 

41 

042 

644 

107 

107 

644 

646 

101 
161 

01 

M 

107 

109 

81 

81 

53 

55 

45 

47 

646 

648 

65 

65 

648 

650 

101 
103 

63 
68 

107 

109 

81 

81 

53 

55 

650 

652 

109 

109 

65 

65 

652 

654 

tea 

108 

68 
06 

81 

83 

41 

41 

054 

050 

109 

109 

47 

47 

656 

G5S 

103 
106 

| 

109 

111 

81 

83 

65 

67 

55 

55 

41 

41 

658 

660 

47 

47 

000 

6(i2 

106 

106 

66 
07 

109 

111 

83 

83 

65 

67 

55 

55 

602 

001 

111 

111 

001 

666 

165 
10T 

107 
167 

83 

83 

GOO 

668 

111 

111 

67 

67 

OOS 

670 

107 

109 

111 

113 

83 

85 

55 

57 

47 

49 

41 

43 

070 

672 

67 

67 

672 

674 

107 

109 

169 
169 

111 

11:5 

83 

85 

55 

57 

47 

49 

41 

43 

674 

676 

113 

113 

676 

07S 

109 
160 

10U 
171 

85 

85 

67 

69 

678 

680 

113 

113 

680 

682 

iTl 

!?! 

113 

115 

85 

85 

67 

69 

57 

r,7 

682 

684 

49 

49 

684 

686 

in 

171 

173 

113 

115 

85 

87 

57 

57 

43 

43 

681) 

688 

115 

115 

69 

6!) 

49 

4'.) 

088 

690 

ITl 
178 

17S 
173 

85 

87 

43 

43 

690 

692 

115 

115 

69 

69 

692 

694 

ITS 
178 

n 

176 

115 

117 

87 

87 

57 

59 

694 

696 

696 

698 

178 

176 

176 

ITi 

115 

117 

87 

87 

69 

71 

57 

59 

49 

51 

698 

700 

117 

117 

700 

4 

6 

8 

10 

12 

14 

16 

TABLE  OF  TWO  CIRCUIT  SINGLE  WINDINGS  FOR  DRUM  ARMATURES. 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES. 

CO 

o: 

0 

i- 

4 

POLES 

6 
POLES 

8 

POLES 

10 

POLES 

12 

POLES 

14 
POLES 

16 

POLES 

No.  OF  CONDUC 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

702 

17:i 

175 

170 
177 

87 

SD 

69 

71 

49 

51 

43 

45 

702 

704 

117 

117 

704 

706 

175 
177 

177 
177 

117 

111) 

87 

89 

59 

59 

43 

45 

706 

708 

71 

71 

708 

710 

177 
177 

177 

179 

117 

11!) 

89 

89 

59 

59 

710 

712 

119 

119 

71 

71 

51 

51 

712 

714 

1T7 

179 

17'J 
179 

89 

89 

714 

716 

119 

Hi) 

51 

61 

716 

718 

179 

17& 
ISt 

119 

121 

89 

91 

71 

73 

59 

61 

45 

45 

718 

720 

720 

722 

17'J 
181 

181 

11  li 

121 

89 

91 

71 

73 

59 

61 

45 

45 

722 

724 

121 

121 

724 

726 

ISl 

183 

91 

91 

51 

53 

726 

728 

121 

121 

73 

73 

728 

730 

na 

163 

121 

123 

91 

91 

61 

61 

51 

53 

730 

.   732 

73 

73 

732 

734 

nw 

185 

121 

123 

91 

93 

61 

61 

45 

47 

7J34 

736 

123 

123 

736 

738 

n 

183 

91 

93 

73 

75 

45 

47 

738 

740 

123 

12:i 

53 

53 

740 

742 

isj 

187 

123 

125 

93 

93 

73 

75 

61 

63 

742 

744 

53 

53 

744 

746 

1»7 

187 

123 

126 

93 

93 

61 

63 

746 

748 

125 

125 

75 

75 

748 

750 

187 

lay 

93 

95 

47 

47 

750 

752 

125 

125 

75 

75 

752 

754 

189 

189 
ISO 

125 

127 

93 

95 

63 

63 

53 

55 

47 

47 

754 

75i  ; 

756 

758 

isu 

iyi 

125 

127 

95 

95 

75 

77 

63 

63 

53 

55 

758 

760 

127 

127 

760 

762 

ibu 
Iffl 

191 

95 

95 

75 

77 

762 

764 

127 

127 

764 

76G 

1UI 

193 

127 

129 

96 

97 

63 

65 

47 

49 

766 

768 

77 

77 

55 

55 

768 

770 

193 

193 
193 

127 

129 

95 

97 

63 

65 

47 

49 

770 

772 

129 

129 

77 

77 

55 

55 

772 

774 

IH 

193 

IH 

.  Ji 

97 

97 

774 

776 

129 

129 

776 

77* 

1U'» 

195 

129 

131 

97 

97 

77 

79 

65 

65 

778 

780 

780 

782 

IN 

197 

129 

131 

97 

99 

77 

79 

65 

65 

55 

57 

49 

49 

782 

784 

131 

131 

784 

786 

11*7 

197 

97 

99 

55 

57 

49 

49 

786 

788 

131 

131 

79 

79 

788 

790 

W 

iyy 

131 

133 

99 

99 

65 

67 

790 

792 

79 

79 

792 

794 

100 

199 

131 

133 

99 

99 

65 

67 

794 

796 

133 

133 

57 

57 

796 

798, 

109 

2D1 

99 

101 

79 

81 

I!) 

51 

798 

800 

133 

133 

57 

57 

800 

4 

6 

8 

10 

12 

14 

16 

WINDING  TABLES   FOR  TWO-CIRCUIT,  DOUBLE  WINDINGS   FOR 

DRUM   ARMATURES. 


TABLE  OF  TWO-CIRCUIT,  DOUBLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

CO 

B 
o 

4 

POLES 

6 
POLES 

8 

POLES 

10 

POLES 

12 
POLES 

14 

POLES 

16 

POLES 

CONDUC1 

F 

RE- 

[NTRANC 

B 

F 

ENTRANC 

B 

F 

RE- 
ENTRANC 

B 

F 

RE- 

ENTRANC 

B 

F 

RE- 

B 

F 

RE- 

B 

F 

RE- 
ENTRANC 

B 

O 
6 

z 

102 

7 

GD 

7 

102 

104 

^'a 

GO 

•J5 

17 

00 

19 

9 

00 

11 

9 

GD 

9 

104 

106 

17 

GD 

17 

11 

GO 

11 

106 

108 

r- 

oo 

27 

22 

15 

SS 

13 

Q 

7 

00 

9 

7 

GD 

7 

108 

110 

19 

GD 

1!) 

110 

112 

H 

GD 

R 

17 

CO 

19 

9 

GO 

9 

112 

114 

11 

GO 

11 

114 

116 

• 

00 

B 

31 

19 

00 

21 

13 
15 

«£ 

15 
15 

11 

oo 

13 

9 

00 

11 

7 

00 

9 

7 

OD 

7 

116 

US 

19 

OO 

19 

118 

120 

31 

GO 

81 

120 

122 

21 

00 

21 

9 

OD 

9 

122 

124 

29 
31 

00 

| 

19 

00 

21 

15 
13 

*8 

B 

11 

oo 

13 

9 

00 

11 

7 

00 

9 

m 

126 

13 

GO 

13 

126 

128 

ill 
33 

CO 

31 
33 

21 

00 

23 

11 

(3D 

11 

128 

130 

21 

GO 

21 

9 

GD 

9 

130 

132 

31 
33 

00 

83 
35 

i? 

°4 

17 
17 

7 

oo 

9 

132 

134 

23 

GO 

23 

13 

GD 

13 

134 

136 

33 
85 

GO 

33 
35 

21 

00 

23 

13 

oo 

15 

11 

GD 

11 

9 

oo 

11 

136 

138 

138 

140 

33 
35 

00 

9 

37 

23 

oo 

25 

17 
17 

n 

17 

19 

11 

00 

13 

9 

GD 

9 

140 

142 

23 

GD 

23 

142 

144 

35 
37 

GD 

35 

87 

13 

oo 

15 

9 

oo 

11 

144 

146 

25 

GD 

25 

15 

GD 

15 

146 

148 

3J 
37 

00 

37 
3V 

23 

oo 

25 

17 
1'J 

%s 

H 

19 

a 

00 

13 

9 

GD 

9 

148 

150 

11 

GD 

11 

150 

152 

87 

39 

GD 

37 

gj 

25 

00 

27 

13 

GD 

13 

152 

154 

25 

GO 

25 

15 

GO 

15 

154 

156 

37 
39 

00 

39 
41 

19 
19 

iV8 

19 

•2\ 

15 

00 

17 

9 

00 

11 

156 

158 

27 

00 

27 

11 

GD 

11 

158 

160 

3? 

GD 

30 
41 

25 

00 

27 

13 

GD 

13 

160 

162 

162 

164 

39 
11 

00 

41 

4U 

27 

oo 

29 

ID 
21 

S£ 

21 

15 

oo 

17 

13 

00 

16 

11 

00 

13 

9 

00 

11 

164 

166 

27 

GO 

27 

17 

GD 

17 

166 

168 

41 
4:1 

GO 

4tf 

168 

170 

29 

GO 

29 

170 

172 

41 
43 

00 

43 

45 

27 

oo 

29 

•21 
21 

S 

ft 

13 

00 

15 

11 

00 

13 

11 

GD 

11 

172 

174 

17 

GO 

17 

174 

176 

u 

OO 

4:1 
46 

29 

00 

31 

17 

00 

19 

15 

GD 

15 

176 

178 

29 

OO 

29 

13 

GD 

13 

178 

180 

fl 

45 

oo 

1? 

21 
2-1 

%8 

11 

11 

GD 

11 

180 

182 

31 

OO 

31 

182 

184 

5 

s 

OO 

3 

17 

29 

oo 

31 

17 

00 

19 

15 

GD 

15 

184 

186 

19 

GD 

19 

13 

GD 

13 

186 

188 

45 
47 

00 

47 
4V 

31 

oo 

33 

28 
23 

W 

23 
25 

15 

00 

17 

11 

00 

13 

188 

190 

31 

GO 

31 

190 

192 

I 

00 

47 

40 

13 

oo 

15 

102 

194 

33 

CD 

33 

12 

GD 

19 

104 

196 

I 

00 

49 
51 

31 

00 

33 

23 
25 

«8 

•2:,       - 
25 

19 

00 

21 

15 

oo 

17 

11 

00 

13 

196 

198 

198 

200 

4!) 
51 

GD 

g 

33 

00 

35 

17 

GD 

17 

13 

oo 

15 

WO 

4 

6 

8 

10 

12 

14 

16 

TWO-CIRCUIT,  DOUBLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

c/> 
<r 
o 

4 

POLES 

6 

POLES 

8 

POLES 

10 

POLES 

12 

POLES 

14 

POLES 

16 

POLES 

CONDUC1 

F 

tte- 

•NTRANC 

B 

F 

RE- 
E  NTRANC 

B 

F 

RE- 
E  NTRANC 

B 

F 

«E- 
E  NTRANC 

B 

F 

R£- 
E  NTRANC 

B 

F 

RE- 
ENTRANC 

B 

F 

RE- 

B 

O 

g 
z 

202 

33 

CE> 

33 

202 

204 

If 

00 

8 

25 
26 

to 

| 

19 

OO 

21 

13 

CE) 

13 

204 

'200 

35 

CE> 

35 

21 

CD 

21 

15 

(SL> 

15 

206 

208 

i 

CO 

53 

33 

00 

35 

17 

GO 

17 

208 

210 

210 

212 

I 

00 

I 

35 

oo 

37 

1 

•& 

27 
27 

17 

oo 

19 

13 

(3D 

13 

212 

214 

35 

GO 

35 

21 

GO 

21 

15 

CE> 

15 

214 

2  1C 

It 

CE> 

B 

21 

00 

23 

210 

218 

37 

CD 

37 

218 

220 

B 

00 

I 

35 

00 

37 

9 

m 

i 

17 

oo 

19 

15 

oo 

17 

13 

oo 

15 

220 

222 

222 

224 

1 

CE> 

B 

37 

00 

39 

21 

00 

23 

19 

GO 

19 

22-1 

22C, 

37 

CE> 

37 

23 

GD 

23 

220 

228 

1 

67 

00 

u 

B 

%8 

n 

15 

oo 

.17 

13 

00 

15 

228 

230 

39 

GO 

39 

230 

2:12 

I 

CE> 

B 

37 

oo 

39 

19 

CD 

10 

232 

234 

23 

GD 

23 

17 

CJD 

17 

234 

230 

B 

oo 

1 

39 

oo 

41 

I 

*8 

B 

23 

00 

25 

19 

oo 

21 

15 

CJD 

15 

236 

2:58 

39 

CJD 

39 

238 

240 

1 

GO 

l 

240 

242 
W 

41 

CD 

41 

17 

CJD 

17 

242 

B 

00 

H 

39 

00 

41 

26 
81 

S 

i 

23 

oo 

25 

19 

oo 

21 

15 

CE> 

15 

244 

240 

25 

CO) 

25 

210 

248 

08 

GD 

1 

41 

oo 

43 

21 

CD 

21 

17 

00 

19 

248 

250 

41 

GO 

41 

250 

'252 

1 

oo 

1 

31 
B 

81 

31 

:<•', 

15 

oo 

17 

252 

254 

43 

GO 

43 

25 

GO 

25 

251 

25(1 

B 

GD 

g 

41 

00 

43 

25 

oo 

27 

21 

GV> 

21 

17 

oo 

19 

250 

"258~ 

258 

260 

B 

oo 

8 

43 

oo 

45 

B 

& 

B 

21 

00 

23 

15 

00 

17 

200 

202 

43 

GO 

43 

19 

CE> 

19 

262 

2(i4 

B 

GD 

or 

25 

oo 

27 

264 

2liti 

45 

CE> 

45 

27 

ru) 

27 

266 

268 

u 

67 

00 

I 

43 

oo 

45 

| 

m 

§ 

21 

00 

23 

17 

GO 

17 

268 

U70 

19 

CE) 

19 

270 

2V  2 

& 

GO 

B 

45 

oo 

47 

23 

CE) 

23 

272 

274 

45 

GO 

45 

27 

CD 

27 

274 

2Vf, 

Si 

oo 

B 

71 

B 

« 

% 

27 

oo 

29 

19 

oo 

91 

17 

GD 

17 

976 

278 

47 

CO) 

47 

278 

280 

?? 

GO 

11 

45 

oo 

47 

93 

CE> 

93 

280 

282 

989 

284 

69 
71 

oo 

i 

47 

00 

49 

« 

n 

§ 

27 

oo 

99 

93 

oo 

95 

19 

00 

91 

17 

oo 

19 

984 

280 

47 

GO 

47 

29 

CE) 

'211 

986 

288 

i 

GO 

IS 

>ss 

290 

49 

GO 

49 

91 

CJD 

91 

>1IO 

292 

71 
73 

00 

78 
76 

47 

00 

49 

B 

•s& 

i 

93 

oo 

95 

17 

oo 

19 

>9-2 

294 

29 

CD 

29 

204 

296 

it 

GO 

B 

49 

oo 

51 

29 

oo 

31 

95 

C5") 

95 

200 

298 

49 

GO 

49 

91 

GD 

91 

298 

300 

75 

oo 

77 

a 

#8 

87 
39 

19 

GD 

19 

300 

4 

6 

8 

10 

12 

14 

16 

TWO-CIRCUIT,  DOUBLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

CONDUCTORS 

4 
POLES 

6 
POLES 

8 

POLES 

10 
POLES 

12 

POLES 

14 

POLES 

16 
POLES 

F 

:»TM~.C, 

B 

F 

RE- 

B 

F 

RE- 

ENTRANC 

B 

F 

EI.TM~.CY 

B 

F 

RE- 

•NTHANCY 

B 

F 

RE- 
ENTRANCY 

B 

F 

RE- 

ENTRANCY 

B 

O 

o 

Z 

302 

51 

CD 

51 

302 

304 

"5 
77 

CD 

-7 

49 

oo 

51 

29 

00 

31 

25 

GO 

25 

21 

00 

23 

304 

306 

31 

CD 

31 

306 

308 

7! 

00 

a 

51 

00 

53 

I 

W 

B 

25 

00 

27 

19 

CD 

19 

308 

310 

51 

CD 

51 

310 

312 

77 
79 

GO 

3 

21 

00 

23 

312 

314 

53 

CD 

53 

31 

CD 

31 

314 

316 

n 

00 

g 

51 

oo 

53 

3» 
39 

SB 

1 

31 

oo 

33 

25 

00 

27 

19 

00 

21 

316 

318 

23 

CD 

23 

318 

320 

i 

CD 

^ 

53 

00 

55 

27 

CD 

27 

320 

•A-l-1 

58 

CD 

53 

322 

324 

H 

oo 

8 

?? 

W 

a 

31 

00 

33 

19 

oo 

21 

324 

326 

55 

CD 

55 

33 

CD 

33 

23 

CD 

23 

326 

328 

u 

83 

CD 

i 

53 

00 

55 

27 

CD 

27 

328 

330 

330 

332 

HI 
83 

00 

8? 
86 

55 

oo 

57 

41 
« 

S8 

1 

27 

00 

29 

23 

oo 

25 

21 

CD 

21 

332 

334 

55 

CD 

55 

33 

CD 

33 

334 

336 

8" 

CD 

I 

33 

oo 

35 

336 

338 

57 

CD 

57 

338 

340 

i 

00 

i? 

55 

oo 

57 

i 

t& 

43 
43 

27 

oo 

29 

23 

00 

25 

21 

CD 

21 

340 

342 

342 

344 

i 

GO 

1 

57 

00 

59 

33 

00 

35 

29 

CO 

29 

344 

346 

57 

CD 

57 

35 

CD 

35 

25 

CD 

25 

34G 

348 

i 

00 

i 

S3 

W 

i 

21 

oo 

23 

348 

350 

59 

CD 

59 

350 

352 

i 

GO 

I 

57 

oo 

59 

29 

CO 

29 

352 

354 

35 

CD 

35 

2B 

CD 

25 

354 

356 

i 

oo 

SB 
ui 

59 

oo 

61 

« 

%8 

8 

35 

oo 

37 

29 

oo 

31 

21 

oo 

23 

356 

358 

59 

CD 

59 

358 

360 

i 

CD 

39 
fll 

25 

00 

27 

3GO 

362 

61 

CD 

61 

302 

364 

89 

| 

oo 

• 
93 

59 

oo 

61 

8 

S8 

i 

35 

oo 

37 

29 

00 

31 

23 

CD 

23 

364 

366 

37 

CD 

37 

366 

368 

91 

03 

CD 

91 
0:1 

61 

00 

63 

31 

CO 

31 

25 

oo 

27 

308 

370 

61 

GO 

61 

370 

372 

H 

93 

oo 

i 

45 
47 

as 

«7 
47 

23 

CD 

23 

372 

374 

63 

CD 

63 

37 

CO 

37 

27 

CD 

27 

374 

376 

1 

CD 

61 

00 

63 

37 

oo 

39 

31 

CD 

31 

376 

378 

378 

380 

| 

00 

95 
tt7 

63 

00 

65 

1 

#8 

47 

49 

31 

00 

33 

23 

00 

25 

380 

382 

63 

GO 

63 

27 

CO 

27 

382 

384 

1 

GO 

lit 

37 

oo 

39 

384 

386 

65 

CiD 

65 

39 

GD 

39 

386 

388 

95 
97 

00 

% 

63 

00 

65 

I 

IB 

| 

31 

oo 

33 

27 

00 

29 

23 

00 

25 

388 

390 

390 

392 

97 
99 

CD 

Si 

65 

00 

67 

33 

CD 

33 

392 

394 

65 

CD 

65 

39 

CO 

3"9 

394 

396 

H 

oo 

3 

i 

£8 

I 

39 

oo 

41 

27 

00 

29 

25 

GO 

25 

396 

398 

67 

CD 

67 

398 

400 

ifl 

GO 

| 

65 

00 

67 

33 

GO 

33 

400 

4 

6 

8 

10 

12 

14 

16 

TWO-CIRCUIT,  DOUBLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

CO 

tr 
o 

4 

POLES 

6 

POLES 

8 
POLES 

10 
POLES 

12 

POLES 

14 
POLES 

16 

POLES 

CONDUC 

F 

RE- 

LNTRANC1 

B 

F 

RE- 
;NTRANC> 

B 

F 

RC- 

ENTRANCY 

B 

F 

RE- 

ENTRANCY 

B 

F 

ENTRANC 

B 

F 

:.TRANCr 

B 

F 

RE- 
ENTRANC 

B 

o 

6 

•z. 

402 

29 

Cft) 

29 

402 

lot 

« 

oo 

115 

67 

OO 

69 

l 

%8 

i 

39 

OO 

•11 

33 

OO 

35 

25 

GO 

25 

404 

406 

67 

C53 

67 

41 

ca) 

41 

406 

408 

I 

CB 

i$ 

408 

410 

69 

ca) 

69 

29 

Cft) 

29 

410 

112 

• 

M 

00 

IS 

67 

oo 

69 

51 
61 

a* 

B 

58 

33 

oo 

35 

25 

00 

27 

112 

414 

41 

ro 

41 

414 

416 

1 

GO 

IS 

69 

oo 

71 

41 

00 

43 

35 

o 

35 

29 

00 

31 

416 

418 

69 

C5) 

69 

418 

120 

i 

oo 

S* 

I 

58 

63 
63 

25 

00 

27 

420 

422 

71 

ca> 

71 

122 

424 

iffi 

ro) 

106 
1UT 

0!) 

oo 

71 

41 

00 

43 

35 

GO 

35 

29 

oo 

31 

421 

120 

12<i 

43 

rtn 

43 

428 

106 
1(H 

00 

13 

71 

oo 

73 

i 

i?8 

8 

35 

oo 

37 

27 

Cft) 

27 

128 

430 

71 

fiD 

71 

31 

CP 

31 

130 

432 

107 

10ft 

fin 

107 
100 

132 

434 

73 

CO) 

73 

43 

fiD 

43 

434 

436 

10; 

1M 

00 

ffi 

71 

oo 

73 

| 

as 

% 

43 

oo 

45 

35 

oo 

37 

27 

Cft) 

27 

436 

438 

31 

Cft) 

31 

438 

440 

109 

in 

rr> 

W 

73 

oo 

75 

37 

Cft) 

37 

440 

112 

73 

Cft) 

73 

442 

444 

109 

111 

oo 

in 

113 

i 

*8 

.... 

67 

43 

00 

45 

31 

oo 

33 

27 

oo 

29 

111 

IK; 

75 

C5) 

75 

45 

CO) 

45 

416 

448 

111 
11* 

C5) 

111 

Q] 

73 

oo 

75 

37 

GO 

37 

448 

•150 

450 

.152 

{15 

00 

113 
116 

75 

00 

77 

R 

^ 

II 

37 

oo 

39 

31 

oo 

33 

27 

00 

29 

452 

.15-1 

75 

Cft) 

75 

45 

Cft) 

45 

454 

456 

11  : 
Hi 

Cft) 

113 
115 

45 

oo 

47 

456 

458 

77 

Cft) 

77 

33 

Cft) 

33 

458 

460 

113 
115 

oo 

H 

75 

oo 

77 

1 

S8 

B 

37 

oo 

39 

29 

GO 

29 

460 

162 

102 

464 

ii? 

Co) 

i 

77 

oo 

79 

45 

00 

17 

39 

Cft) 

39 

464 

Kit; 

77 

GO 

77 

47 

GO 

47 

33 

Cft) 

33 

466 

468 

i!? 

oo 

117 
lift 

i 

«j 

| 

29 

Cft) 

29 

468 

470 

79 

C® 

79 

170 

472 

117 

119 

OO 

fii 

77 

oo 

79 

39 

GO 

39 

33 

oo 

86 

172 

474 

47 

Cft) 

47 

474 

476 

i 

oo 

18 

79 

oo 

81 

B 

« 

§ 

47 

00 

49 

39 

oo 

41 

29 

oo 

31 

476 

478 

79 

Cft) 

79 

178 

480 

• 

Cft) 

119 

121 

33 

oo 

35 

180 

482 

81 

CO 

81 

182 

181 

119 

121 

oo 

121 

12:1 

79 

oo 

81 

1 

«fi 

Q 
61 

47 

oo 

49 

39 

oo 

11 

29 

oo 

31 

181 

180 

49 

Cft) 

49 

35 

Cft) 

35 

48li 

488 

121 

<;; 

CD 

ffi 

81 

oo 

83 

41 

GO 

41 

188 

490 

81 

ca) 

81 

490 

492 

I 

oo 

ffl 

a 

ffl 

& 

31 

(S3 

31 

192 

494 

83 

rr> 

83 

49 

cm 

49 

35 

Cft) 

35 

494 

496 

133 
1*6 

GO 

123 
125 

81 

oo 

83 

19 

00 

51 

41 

Cft) 

41 

196 

498 

198 

500 

i 

00 

126 

127 

83 

oo 

85 

a 

&S 

03 

(.  ; 

41 

oo 

43 

35 

oo 

37 

31 

Cft) 

31 

500 

4 

6 

8 

10 

12 

14 

16 

TWO-CIRCUIT,  DOUBLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

CONDUCTORS 

4 

POLES 

6 

POLES 

8 

POLES 

10 

POLES 

12 

POLES 

14 

POLES 

16 

POLES 

F 

RE- 

B 

F 

RE- 
ENTRANCV 

B 

F 

ENTRANCY 

B 

F 

ENTRANCE 

B 

F 

RE- 

B 

F 

BE- 
ENTRANCY 

B 

F 

RE- 
ENTHANCY 

B 

O 

0 

z 

502 

83 

GD 

83 

502 

504 

126 

m 

(33 

i 

±9 

00 

51 

504 

506 

85 

(33 

85 

51 

fo) 

51 

506 

508 

125 

r.7 

oo 

127 
129 

83 

00 

85 

03 
03 

SB 

63 
05 

41 

00 

43 

35 

OO 

37 

31 

OO 

33 

508 

510 

510 

512 

127 
129 

C53 

127 
129 

85 

00 

87 

43 

GO 

43 

512 

514 

85 

(33 

85 

51 

rs3 

51 

37 

GD 

37 

514 

51  G 

It] 

129 

oo 

1$ 

63 
65 

&S 

05 
05 

51 

oo 

53 

31 

00 

33 

516 

518 

87 

(33 

87 

518 

520 

12B 

(33 

I 

85 

00 

87 

43 

fa) 

43 

520 

522 

37 

GO 

3V 

522 

524 

1 

oo 

ffl 

87 

00 

89 

1 

SB 

i 

51 

00 

53 

43 

00 

45 

33 

GD 

33 

52-1 

526 

87 

GO 

87 

53 

fE) 

53 

526 

528 

131 
133 

rT> 

131 
133 

37 

oo 

39 

528 

530 

89 

GD 

89 

530 

532 

131 
133 

oo 

133 
135 

87 

00 

89 

i 

&S 

61 
07 

43 

00 

45 

33 

(33 

33 

532 

534 

53 

(S3 

53 

534 

536 

i 

fa) 

133 

135 

89 

00 

91 

53 

oo 

55 

45 

GD 

45 

37 

oo 

39 

536 

538 

89 

ra) 

89 

5i!8 

540 

i 

oo 

136 
137 

07 
67 

SB 

i 

33 

00 

35 

540 

542 

91 

fa) 

91 

39 

GO 

39 

542 

544" 

135 
137 

(3) 

135 
137 

89 

00 

91 

53 

00 

55 

45 

fa) 

45 

544 

54G 

55 

(33 

55 

540 

518 

135 
137 

oo 

137 
139 

91 

00 

93 

8 

as 

§ 

45 

oo 

47 

33 

oo 

35 

548 

550 

91 

ra) 

91 

39 

GO 

39 

55(1 

552 

i 

GD 

la: 

552 

554 

93 

CD 

93 

55 

(33 

55 

554 

556 

! 

00 

\8 

91 

oo 

93 

1 

SB 

?! 

55 

oo 

57 

45 

oo 

47 

39 

oo 

41 

35 

GO 

35 

556 

558 

558 

560 

ffi 

GD 

ffl 

93 

00 

95 

47 

fft3 

47 

560 

562 

93 

(33 

93 

562 

501 

ffl 

00 

I 

B 

%8 

a 

55 

oo 

57 

39 

oo 

41 

35 

GD 

35 

564 

566 

95 

ra) 

95 

57 

(33 

57 

5G6 

568 

i 

GD 

iU 

93 

00 

95 

47 

fa3 

47 

5GS 

570 

41 

GD 

41 

570 

572 

& 

CO 

143 
145 

95 

00 

97 

71 

H 

ffl 

a 

47 

oo 

49 

35 

oo 

37 

572 

574 

95 

GD 

95 

57 

r»3 

57 

574 

57G 

143 
145 

ra) 

143 

n;> 

57 

oo 

59 

57G 

578 

1)7 

fa) 

97 

41 

ro) 

41 

578 

580 

143 
146 

00 

145 
147 

95 

00 

97 

i 

fig 

78 

73 

47 

oo 

49 

35 

oo 

37 

580 

582 

582 

584 

145 
147 

(S3 

145 
147 

97 

00 

99 

57 

00 

59 

49 

fa3 

49 

41 

oo 

43 

584 

586 

97 

GD 

97 

59 

(33 

59 

586 

588 

110 
147 

00 

147 

149 

i 

SB 

,S 

37 

GD 

37 

588 

590 

99 

ra) 

99 

590 

592 

147 

149 

GD 

147 

149 

97 

00 

99 

49 

(33 

49 

41 

oo 

43 

592 

594 

59 

(33 

59 

591 

596 

147 
H9 

00 

149 
151 

99 

00 

101 

?S 

&S 

77. 

69 

00 

61 

49 

oo 

51 

37 

(33 

37 

59G 

598 

99 

GD 

99 

43 

GD 

43 

598 

600 

161 

GD 

151 

GOO 

4 

6 

8 

10 

12 

14 

16 

TWO-CIRCUIT,  DOUBLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

a> 

cc 
o 

1- 

4 

POLES 

6 
POLES 

8 
POLES 

10 
POLES 

12 

POLES 

14 
POLES 

16 

POLES 

•  CONDUC 

F 

RE- 
ENTRANCV 

B 

F 

RE- 
EMTRAMO 

B 

F 

RE- 
ENTRANCY 

B 

F 

RE- 
ENTRANCY 

B 

F 

RE* 
ENTRANCY 

B 

F 

ENTRAMCY 

B 

F 

RE- 
ENTRANC 

B 

O 
6 

z 

602 

101 

GO 

101 

602 

604 

«$ 

oo 

m 

99 

oo 

101 

i 

SB 

i 

59 

OO 

61 

49 

00 

51 

37 

OO 

39 

604 

MX; 

61 

(5) 

61 

43 

OO 

43 

606 

r.iis 

I 

GO 

is 

101 

oo 

103 

51 

OO 

51 

608 

roo 

101 

(5) 

101 

610 

612 

161 
158 

oo 

18 

i 

48 

« 

43 

00 

45 

37 

oo 

39 

012 

614 

103 

(S3 

103 

61 

00 

61 

014 

616 

HI 

165 

GO 

S 

101 

oo 

103 

61 

00 

63 

51 

OO 

51 

616 

618 

618 

620 

m 

oo 

m 

103 

oo 

105 

77 
77 

& 

77 
79 

51 

oo 

53 

43 

00 

45 

n 

GO 

39 

620 

622 

103 

GO 

103 

622 

624 

m 

167 

(S3 

1 

61 

oo 

63 

624 

626 

J05 

CO) 

105 

63 

GO 

63 

45 

OO 

45 

626 

628 

HI 

oo 

167 
169 

103 

00 

105 

77 
79 

as 

79 
79 

51 

O  0 

53 

39 

OO 

39 

628 

630 

630 

632 

167 

16» 

(S3 

167 
169 

105 

oo 

107 

53 

00 

53 

632 

63"4 

105 

(S3 

105 

63 

00 

63 

45 

GO 

45 

634 

0:10 

I 

oo 

ffi 

S 

« 

79 
81 

63 

oo 

65 

39 

oo 

41 

636 

638 

107 

00 

107 

638 

(MO 

16» 
101 

(30 

15V 
101 

105 

oo 

107 

53 

GO 

53 

45 

00 

47 

640 

642 

642 

644 

ffi 

oo 

tt 

107 

oo 

109 

i 

as 

fl 

63 

00 

65 

53 

oo 

55 

39 

oo 

41 

644 

040 

107 

oo 

107 

65 

ro> 

65 

040 

648 

I 

(S3 

i 

45 

oo 

47 

048 

650 

109 

oo 

109 

050 

652 

ft 

oo 

18 

107 

00 

109 

| 

Mj 

§1 

53 

oo 

55 

41 

00 

41 

652 

654 

65 

00 

65 

47 

00 

47 

054 

656 

i 

GO 

$ 

109 

00 

111 

65 

oo 

67 

55 

OO 

55 

050 

058 

109 

go 

109 

058 

660 

',.'. 

oo 

at 

3 

as 

| 

41 

GO 

41 

660 

662 

111 

(53 

111 

47 

OO 

47 

662 

664 

i 

GO 

106 
107 

109 

oo 

111 

65 

oo 

67 

55 

GO 

55 

004 

666 

67 

OO 

67 

666 

668 

B 

.0 

167 
1G» 

111 

00 

113 

i 

ss 

,: 

55 

0  0 

57 

47 

00 

49 

41 

00 

43 

008 

670 

111 

OO 

111 

070 

672 

% 

(53 

» 

672 

674 

113 

(S3 

11:5 

67 

GO 

67 

074 

676 

1C7 
1C9 

oo 

i 

111 

00 

118 

B 

aj 

I 

67 

00 

69 

55 

oo 

57 

47 

oo 

48 

41 

oo 

,43 

676 

6V8 

078 

080 

fi 

(SO 

«» 

113 

oo 

115 

57 

GO 

57 

080 

(182 

113 

GO 

113 

49 

GO 

49 

082 

<;s  t 

18 

00 

171 

i,-; 

; 

SB 

• 

Si 

67 

oo 

69 

43 

GO 

43 

084 

G8C 

115 

CO 

115 

69 

GO 

69 

686 

68J 

a 

GO 

i 

113 

oo 

115 

57 

00 

57 

088 

C'.M) 

49 

OO 

49 

091) 

092 

a 

;-  0 

lit 

115 

00 

117 

% 

&3 

87 

B 

57 

oo 

59 

43 

(i) 

43 

092 

094 

115 

GO 

115 

69 

GO 

69 

094 

696 

in 

176 

GO 

173       i 
176 

69 

oo 

71 

49 

00 

51 

090 

6(J« 

117 

OO 

117 

098 

700 

i 

oo 

176 
177 

115 

00 

117 

| 

W 

1 

57 

00 

51) 

43 

oo 

45 

700 

4 

6 

8 

10 

12 

14 

16 

TWO-CIRCUIT,  DOUBLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

CO 
CE 
O 

4 

POLES 

6 
POLES 

8 

POLES 

10 
POLES 

12 

POLES 

14 

POLES 

16 

POLES 

CONDUC" 

F 

RE- 

B 

F 

RE- 

ENTHAr«CV 

B 

F 

ENTRANCY 

B 

F 

RE- 

ENTRANCY 

B 

F 

tNTHANCY 

B 

F 

RE- 
ENTRANCV 

B 

F 

RE- 
ENTRANCV 

B 

o 

6 

Z 

702 

702 

704 

17o 
177 

GO 

ITS 
177 

117 

OO 

119 

69 

OO 

71 

59 

CD 

59 

49 

OO 

51 

704 

706 

117 

rg) 

117 

71 

C5) 

71 

706 

708 

I 

oo 

177 
179 

i 

°cS 

i 

43 

OO 

45 

708 

710 

119 

CP 

119 

51 

fa) 

51 

710 

712 

ffi 

fa) 

177 
179 

117 

0  0 

119 

59 

CE> 

59 

712 

714 

71 

£52 

71 

714 

716 

iS 

oo 

IV'.' 

iai 

119 

oo 

121 

i 

S8 

9 

71 

oo 

73 

59 

oo 

61 

45 

CO) 

45 

716 

718 

119 

fp 

119 

51 

(5) 

51 

718 

720 

m 

ffi) 

119 

720 

722 

121 

CP 

121 

722 

724 

•is 

oo 

181 
183 

119 

oo 

121 

i 

as 

i 

71 

00 

73 

59 

oo 

M 

51 

oo 

53 

45 

C® 

45 

724 

726 

73 

OD 

73 

726 

728 

181 
183 

CP 

181 

UP 

121 

00 

123 

61 

nn 

61 

728 

730 

121 

(V 

121 

730 

732 

181 

183 

oo 

183 
gj 

& 

«8 

8 

51 

oo 

53 

45 

oo 

47 

732 

734 

123 

CP 

123 

73 

OC 

73 

734 

736 

l$B 

..:_-'>_ 

CP 

188 

1H1 

121 

00 

123 

73 

oo 

75 

61 

C9) 

61 

736 

738 

53 

CD 

53 

738 

740 

183 
'1H6 

oo 

186 
'187 

123 

00 

125 

i 

«8 

^ 

61 

oo 

<;:>, 

45 

oo 

47 

740 

742 

123 

fp 

123 

742 

714 

185 
187 

CP 

186 
187 

73 

oo 

75 

744 

746 

125 

(V 

125 

75 

rs? 

75 

53 

fp 

53 

746 

748 

185 
187 

00 

i 

123 

00 

125 

93 
98 

§8 

i 

61 

00 

63 

47 

GD 

47 

748 

750 

750 

752 

187 

18« 

fp 

ffi 

125 

oo 

127 

63 

CP 

63 

53 

oo 

55 

752 

754 

125 

cp 

125 

75 

£2 

75 

754 

756 

J87 

189 

oo 

189 
191 

93 
95 

%8 

8 

75 

oo 

77 

47 

CD 

47 

756 

758 

127 

CP 

127 

758 

760 

.189 

m 

CO) 

189 
191 

125 

00 

127 

63 

fa) 

63 

53 

oo 

55 

760 

762 

762 

764 

i>'j 

191 

oo 

.191 
193 

127 

oo 

129 

95 
95 

ffl 

i 

75 

00 

77 

63 

00 

65 

47 

00 

49 

764 

766 

127 

CP 

127 

77 

rso 

77 

55 

ca) 

55 

766 

768 

m 

m 

CP 

191 
193 

768 

770 

125 

fa) 

129 

770 

772 

« 

00 

193 
195 

127 

00 

129 

95 
97 

«! 

5i 

63 

oo 

65 

47 

00 

49 

772 

774 

77 

(ID 

77 

55 

fp 

55 

774 

776 

g 

m 

193 

JOB 

129 

00 

131 

77 

00 

79 

65 

<D 

65 

776 

778 

129 

CP 

129 

778 

780 

n 

195 

00 

196 
197 

97 
97 

S8 

97 

99 

55 

oo 

57 

49 

OD 

49 

780 

782 

131 

CP 

131 

782 

784 

BE 

197 

(S3 

98 

197 

129 

00 

131 

77 

00 

79 

65 

ca) 

65 

784 

780 

79 

CE» 

79 

786 

788 

uK 

197 

oo 

197 
199 

131 

00 

133 

97 
99 

%8 

g 

65 

oo 

67 

55 

oo 

57 

49 

ca) 

49 

788 

790 

131 

CP 

131 

790 

792 

197 

in 

o 

191 
19l< 

792 

794 

133 

GO 

133 

79 

fp 

79 

57 

ca) 

57 

791 

796 

197 

m 

00 

is; 

131 

oo 

133 

8S 

^ 

H 

101 

79 

oo 

81 

65 

00 

67 

49 

oo 

51 

796 

798 

798 

800 

g 

CO 

a 

133 

oo 

135 

800 

4 

6 

8 

10 

12 

14 

16 

WINDING   TABLES   FOR   TWO-CIRCUIT,    TRIPLE  WINDINGS   FOR 

DRUM   ARMATURES. 


TABLE  OF  TWO-CIRCUIT,  TRIPLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

05 

c 

o 

4 

POLES 

6 

POLES 

8 
POLES 

10 

POLES 

12 
POLES 

14 
POLES 

16 
POLES 

CONDUC- 

F 

;NT»Lv 

B 

F 

•NlLcv 

B 

F 

eNTRANCV 

B 

F 

RE- 
ENTRANCY 

B 

F 

ftE- 

ENTRANC 

B 

F 

RE- 

B 

F 

JLc 

B 

o 

6 

•z. 

102 

23 
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000 

25 
27 

16 
17 

Svc 

17 

ly 

11 

000 

13 

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1 

5 

ooo 

7 

102 

104 

11 

CfiD 

11 

7 

as) 

7 

104 

106 

i 

(55) 

25 

29 

13 

(55) 

15 

9 

(55) 

11 

7 

(55) 

9 

7 

(55) 

7 

106 

108 

17 
19 

(55) 

1 

108 

110 

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(99) 

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13 

(55) 

13 

110 

112 

112 

114 

27 
29 

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17 

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OOO 
CoS 

ij 

15 

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15 

11 

coo 

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g 

114 

116 

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(55) 

11 

116 

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27 
31 

(55) 

29 
31 

13 

(55) 

15 

7 

(55) 

9 

7 

(55) 

7 

118 

120 

% 

SvS 

i 

9 

000 

9 

120 

122 

1 

(55) 

33 

15 

(55) 

17 

7 

(55) 

9 

122 

124 

ia 

M 

13 

124 

126 

29 
33 

000 

8 

11) 
21 

(55) 

23 

15 

ooo 

15 

11 

ooo 

13 

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s 

11 
11 

120 

128 

128 

130 

B 

f55) 

8 

17 

(5D 

17 

130 

132 

21 

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23 

9 

ooo 

9 

132 

134 

31 

g 

(55) 

1 

15 

(55) 

17 

13 

(55) 

15 

9 

(55) 

11 

7 

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9 

134 

136 

13 

(99) 

13 

136 

138 

i 

000 

33 
37 

23 

Sv8 

K 
B 

17 

000 

19 

11 
11 

5^o 

11 

13 

9 

000 

9 

138 

140 

140 

142 

E 

(55) 

36 
37 

17 

(55) 

17 

142 

144 

1 

(55) 

g 

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15 

144 

146 

35 

37 

(55) 

35 
W 

19 

(55) 

19 

13 

(55) 

15 

9 

(55) 

11 

146 

148 

11 

(55) 

11 

148 

150 

85 
89 

coo 

37 
39 

I 

ooo 
GoiD 

26 
27 

17 

000 

19 

u 

'  -Zj.1.1 

13 
13 

9 

ooo 

9 

150 

152 

152 

154 

37 
39 

(55) 

I 

19 

(55) 

21 

15 

(55) 

17 

9 

(55) 

11 

154 

156 

i 

Stfti 

i 

15 

000 

15 

156 

158 

ft 

as) 

i 

19 

(M) 

13 

158 

ItiU 

11 

(55) 

11 

160 

162 

41 

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43 

• 
27 

(99) 

27 
29 

21 

ooo 

2i 

3 

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i 

11 

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n 

162 

164 

17 

(99) 

17 

164 

166 

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(99) 

41 
43 

19 

(98) 

21 

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(55) 

17 

9 

(55) 

11 

160 

168 

27 
2U 

;—; 

27 

20 

168 

170 

6 

(55) 

41 
46 

21 

(S5J 

2:', 

11 

(99) 

11 

170 

172 

172 

174 

1 

ooo 

'  46 

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i 

21 

000 

21 

17 

000 

19 

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16 
16 

11 

ooo 

13 

17J 

1V6 

17 

(55) 

17 

13 

(55) 

13 

176 

178 

46 

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3 

47 

23 

Casi) 

23 

178 

180 

15 

(55) 

i 

180 

182 

a 

47 

&a> 

B 

4,7 

21 

CM? 

23 

11 

(55) 

11 

182 

183 

19 

(98) 

19 

184 

186 

I 

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46 
49 

1? 

%$ 

31 
33 

23 

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25 

17 

ooo 

19 

16 
15 

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16 

11 

000 

13 

186 

188 

13 

(55) 

13 

188 

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8 

Cas) 

47 
49 

23 

(9,9) 

23 

13 

(55) 

15   1 

190 

192 

i 

CojQ 
OTTO 

31 
33 

192 

194 

47 
49 

(sa) 

I 

25 

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25 

19 

(59) 

2] 

1  94 

196 

19 

(55) 

19 

196 

198 

M 

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33 

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£ 

23 

ooo 

25 

16 
17 

s 

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17 

11 

000 

13 

198 

200 

200 

4 

6 

8 

10 

12 

14 

16 

TABLE  OF  TWO-CIRCUIT,  TRIPLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.  OF  CONDUCTORS 

FRONT  AND  BACK.  PITCHES 

CO 
E 

0 

4 

POLES 

6 
POLES 

8 

POLES 

10 

POLES 

12 

POLES 

14 

POLES 

16 

POLES 

CONDUC" 

F 

RE- 

ENTRANCI 

B 

F 

RE- 

B 

F 

HE- 
ENTRANCY 

B 

F 

RE- 
ENTRANCV 

B 

F 

RE- 

EHTRANCY 

B 

F 

RE- 
ENTRANC 

B 

F 

E«T"NC 

B 

O 

d 

Z 

202 

I 

(55) 

49 
63 

25 

(55) 

27 

13 

(55) 

15 

13 

(aa> 

13 

202 

204 

is 

BBS 

1 

21 

OOO 

21 

15 

ooo 

15 

204 

206 

8 

(55) 

I 

25 

(W> 

25 

19 

r?5) 

21 

20(5 

208 

208 

210 

1 

ooo 

1 

3 

fSXi 

OTTO 

86 

37 

27 

ooo 

27 

{? 

S^ 

\i 

210 

212 

212 

214 

B 

(as) 

If 

25 

(55) 

27 

21 

(as) 

23 

13 

(55) 

13 

214 

216 

35 
37 

(55) 

86 
37 

21 

ooo 

21 

15 

ooo 

15 

216 

218 

1 

(55) 

| 

27 

(55) 

29 

15 

f«9~) 

17 

13 

^55) 

15 

218 

1220 

220 

222 

1 

ooo 

i 

% 

OOP 
G33 

B 

27 

000 

27 

17 

H 

ass 

u 

IV 

222 

224 

23 

(55) 

23 

224 

226 

u 

u 

(99") 

B 

29 

Coo) 

29 

21 

(99) 

23 

226 

22S 

XI 

39 

oVo 

,-. 
so 

228 

230 

1 

(to 

g 

27 

<?») 

29 

15 

(55) 

17' 

13 

(55) 

15 

230 

232 

17 

<w> 

17 

232 

'234 

67 
6» 

ooo 

i 

! 

(55) 

i 

29 

ooo 

31 

23 

ooo 

25 

i 

^ 

B 

15 

000 

15 

234 

236 

23 

f99) 

23 

236 

238 

i 

(99) 

8? 

29 

(99) 

29 

238 

240 

I 

S£? 

1 

240 

242 

B 

(99> 

8 

31 

(55) 

31 

242 

244 

25 

(95) 

25 

17 

(55) 

17 

244 

210 

H 

ooo 

B 

1 

oVo 

41 

43 

29 

ooo 

31 

23 

ooo 

25 

B 

trtfo 

| 

17 

000 

19 

15 

000 

15 

240 

-is 

248 

250 

01 

63 

(98) 

1 

31 

(99^ 

33 

15 

(aa) 

17 

250 

252 

41 
43 

(55) 

41 
48 

252 

254 

3 

«5 

<5S) 

B 

31 

C99) 

31 

25 

(aa) 

27 

254 

250 

25 

(55) 

25 

256 

258 

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1 

41 
43 

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8 

B8 

ooo 

33 

21 

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is 

17 

ooo 

19 

258 

260 

19 

(99) 

19 

2(iO 

262 

62 

n 

(aa) 

i 

31 

aiD 

33 

15 

(aa) 

17 

262 

2(14 

B 

WTO 

B 

27 

000 

27 

2(5-1 

26(3 

I 

(55) 

06 

69 

33 

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35 

25 

(55) 

27 

17 

(W) 

17 

2(i<! 

268 

208 

27(1 

5 

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ooo 

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ft» 

B 

(55) 

B 

33 

ooo 

33 

21 
23 

8fg 

I 

270 

272 

19 

(55) 

19 

272 

274 

81 

(as) 

1 

• 

35 

(9JZ) 

35 

27 

(55) 

29 

19 

(as) 

21 

274 

27(5 

1 

i^§ 

I 

27 

ooo 

27 

276 

278 

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aa) 

09 
71 

33 

(aa) 

35 

17 

(55) 

17 

278 

280 

280 

282 

?! 

ooo 

B 

| 

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$ 

35 

ooo 

37 

5 

23 

ODD 

2a 

25 

17 

ooo 

19 

282 

2X1 

2'.) 

(99) 

2'.) 

284 

286 

5 

73 

(aa) 

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35 

(9fi) 

35 

27 

f55) 

29 

19 

S5) 

fll 

286 

28S 

47 
Vt 

(M> 

1 

21 

000 

21 

288 

290 

B 

(55) 

75 

37 

(98) 

37 

•.".Ml 

295 

292 

294 

i 

ooo 

'7! 

4B 

j£3 

49 

61 

35 

ooo 

37 

29 

ooo 

31 

23 

W 

| 

17 

000 

19 

994 

296 

29 

(55) 

29 

296 

298 

73 

75 

(55) 

B 

37 

(89) 

39 

19 

J2£)_ 

V) 

998 

300 

B 

irVi 

4U 
61 

21 

ooo 

fll 

300 

4 

6 

8 

10 

12 

14 

16 

TABLE  OF  TWO-CIRCUIT,  TRIPLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

No.OF  CONDUCTORS 

4 

POLES 

6 
POLES 

8 

POLES 

10 
POLES 

12 

POLES 

14 
POLES 

16 

POLES 

F 

E»i"r«cv 

B 

F 

ENTHANCV 

B 

F 

RE- 
ENTRANCY 

B 

F 

EKTMNCY 

B 

F 

RE- 

B 

F 

RE- 
ENTRANCY 

B 

F 

ENTRANCY 

B 

302 

n 

77 

(55) 

75 
77 

37 

(55) 

37 

21 

(22) 

23 

302 

304 

31 

(55) 

31 

304 

306 

75 

77 

OOJ 

R 

70 

i 

(99) 

I 

39 

ooo 

39 

29 

000 

31 

•::.. 
26 

^S 

i§ 

306 

308 

308 

310 

7» 

(55) 

i 

37 

(<39) 

39 

19 

(99") 

19 

310 

312 

a 

u 

^ 

53 

312 

314 

77 
79 

(29) 

77 
B 

39 

(82) 

41 

31 

(55) 

33 

21 

faa) 

23 

19 

(89") 

21 

314 

316 

31 

(99) 

31 

23 

(99) 

23 

316 

318 

i 

ooo 

n 

u 

& 

se% 

R 

39 

ooo 

39 

25 

'J7 

SV? 

i 

318 

320 

320 

322 

o 

jn 

f® 

79 

H 

41 

(asD 

41 

322 

324 

8 

(58) 

^ 

33 

ooo 

33 

324 

326 

7» 

S3 

(22) 

81 
S3 

39 

(2S) 

41 

31 

(2S) 

33 

19 

(22) 

21 

326 

328 

n 

(92) 

23 

328 

330 

1 

ooo 

S 

g 

^ 

S  ' 

41 

ooo 

43 

•:, 
27 

jDJiO 

E 

23 

ooo 

25 

21 

ooo 

21 

330 

332 

332 

334 

i 

(99) 

n 

86 

41 

(99) 

41 

33 

(22) 

35 

334 

336 

| 

GTS 
ooo 

56 
67 

33 

000 

33 

336 

338 

"4 

(99) 

« 

43 

r?g) 

-13 

338 

340 

340 

342 

B 

ooo 

• 

B 

56 
57 

(99) 

B 

41 

ooo 

43 

E 

;-.•:, 

?';: 

23 

oor. 

25 

21 

ooo 

21 

342 

344 

35 

(99) 

86 

25 

(55) 

25 

344 

346 

85 
87 

(5?) 

8,r. 

B 

43 

(55) 

45 

33 

(22) 

35 

21 

(99) 

23 

346 

348 

n 

H 

^ 

| 

348 

350 

85 

89 

(5?) 

fl 
H 

43 

(9B) 

43 

350 

352 

352 

354 

87 

H 

ooo 

87 
91 

;•: 

69 

S,;-J 

69 
SI 

4J 

000 

45 

35 

000 

37 

I 

S^J 

i 

354 

356 

35 

(55) 

35 

25 

(55) 

25 

356 

358 

87 

Ul 

(551 

• 

91 

43 

fas) 

45 

25 

(§5) 

27 

21 

(92) 

23 

358 

360 

0? 

(aa) 

B 

el 

360 

362 

8 

(59) 

89 
98 

45 

(as) 

47 

23 

(22) 

23 

362 

364 

37 

(99) 

37 

364 

366 

89 
93 

000 

91 

H 

H 

61 

sag 

01 
03 

45 

ooo 

45 

35 

ooo 

37 

t 

8K 

i 

366 

368 

368 

370 

91 

'.'.; 

(55) 

91 

B 

47 

(29) 

47 

25 

(99) 

27 

370 

372 

B 

S3 

oVo 

01 

03 

27 

ooo 

27 

372 

374 

H 

'...•. 

(55) 

93 
96 

45 

Caa) 

47 

37 

(55) 

39 

23 

(99) 

23 

374 

376 

37 

(55) 

37 

370 

37S 

93 

B 

ooo 

93 
97 

I 

(90) 

S 

47 

000 

49 

i 

® 

81 
88 

23 

000 

25 

378 

380 

380 

382 

93 
87 

(55) 

B 

47 

(as) 

47 

382 

384 

| 

SiS 

1 

39 

ooo 

39 

27 

ooo 

27 

381 

386 

95 
97 

(99) 

95 
99 

49 

(as) 

49 

37 

(55) 

39 

27 

(98) 

29 

386 

388 

388 

390 

96 
«9 

ooo 

g 

B 

05 

CS/oD 
ooo 

06 
67 

47 

ooo 

49 

81 

88 

crtjo 

88 
88 

23 

000 

25 

390 

392 

392 

394 

97 
Ut» 

f99) 

f7 
_    l"l 

49 

(99) 

51 

39 

r?«) 

41 

25 

(99) 

25 

394 

396 

8? 

(22) 

67 

39 

ooo 

39 

396 

398 

07 
101 

(58) 

99 
101 

49 

(99) 

49 

27 

(99) 

29 

398 

400 

29 

(99) 

29 

400 

4 

6 

8 

10 

12 

14 

16 

TABLE  OF  TWO-CIRCUIT,  TRIPLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

No.  OF  CONDUCTORS 

4 
POLES 

6 

POLES 

8 
POLES 

10 

POLES 

12 

POLES 

14 

POLES 

16 

POLES 

F 

RE- 
ENTRANCY 

B 

F 

RC- 
ENTRAHCY 

B 

F 

RE* 
ENTRANCV 

B 

F 

ENTR^Cr 

B 

F 

RE- 
ENTRANCY 

B 

F 

RE- 
CNTRANCY 

B 

F 

RE- 

ENTRANCY 

B 

402 

i 

000 

,$ 

?r 

^ 

61 
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51 

OOO 

51 

• 

as. 

OOO 
GS> 

S3 
36 

402 

404 

41 

(99) 

41 

404 

406 

•a 

(as) 

KJ 

49 

(® 

51 

39 

(55) 

41 

25 

(5a) 

25 

406 

408 

I 

CCQ 
OTJo 

Si 

408 

410 

101 
108 

(99) 

us 

51 

(90) 

53 

25 

iW) 

27 

410 

412 

29 

(SS) 

29 

412 

414 

| 

ooo 

iisi 

0 

w 

(aa) 

fl 

51 

ooo 

51 

41 

ooo 

43 

a 

3& 

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i 

29 

ooo 

31 

414 

416 

41 

<sa) 

41 

416 

418 

i 

(2JD 

IE 

53 

(2fl) 

53 

418 

420 

B 

SftS 

1 

420 

422 

i 

(90) 

it* 

51 

(99) 

53 

25 

(90) 

27 

422 

424 

43 

(99) 

43 

424 

426 

1 

ooo 

iss 

B 

71 

S^o 

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53 

000 

55 

41 

ooo 

43 

| 

C  r.~o 

31 

29 

OGO 

31 

27 

000 

27 

420 

428 

31 

(S) 

31 

428 

430 

i 

(99) 

Kl 

53 

(9$ 

53 

430 

432 

g 

(5a) 

g 

432 

i:tl 

I 

(SS) 

ffl 

55 

(5a) 

55 

43 

(5D 

45 

434 

436 

43 

(59) 

43 

436 

438 

B 

000 

ffl 

% 

?£« 

B 

53 

000 

;-.-) 

36 
S7 

ftft? 

1 

27 

ooo 

27 

438 

440 

31 

(99) 

31 

140 

442 

ffi 

ft?) 

KJV 
118 

55 

C99) 

57 

31 

(sS) 

33 

27 

(99) 

29 

442 

444 

i 

oV6 

M 

45 

oco 

45 

444 

446 

10W 
1l8 

(88) 

111 
11» 

55 

<99) 

55 

43 

(9?) 

45 

440 

448 

448 

450 

I 

ooo 

ill 

78 
76 

r«R) 

76 

77 

57 

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57 

3 

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37 
39 

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152 

151 

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55 

(2S) 

57 

45 

(90) 

47 

31 

(99) 

33 

27 

(20) 

29 

454 

456 

ft 

^ 

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45 

000 

45 

33 

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33 

456 

458 

B 

(aa) 

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57 

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59 

29 

(98) 

29 

458 

460 

400 

402 

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77 
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57 

000 

57 

I 

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39 
S9 

462 

401 

47 

(99") 

47 

404 

loo 

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59 

(9ft 

59 

45 

(SS) 

47 

406 

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B 

w 

77 
79 

jj§ 

ooo 

33 

468 

470 

119 

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57 

(99) 

59 

33 

(?9) 

35 

•2'.) 

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29 

470 

4V  2 

472 

474 

W 

ooo 

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77 
79 

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B 

59 

ooo 

61 

47 

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49 

30 
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8 

29 

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474 

476 

47 

r«9) 

47 

476 

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59 

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59 

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480 

482 

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61 

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61 

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484 

49 

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49 

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35 

484 

486 

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59 

000 

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47 

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49 

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29 

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31 

480 

488 

48,8 

490 

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61 

(99) 

63 

31 

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31 

490 

492 

61 

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81 

83 

492 

494 

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121. 

(99) 

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61 

(SA) 

01 

49 

(99) 

51 

404 

496 

49 

(99) 

49 

35 

(99) 

35 

496 

4118 

B 

B 

ooo 

$ 

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S 

63 

000 

63 

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35 

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41)8 

500 

500 

4 

6 

8 

10 

12 

14 

46 

TASLE  OF  TWO-CIRCUIT,  TRIPLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

CO 

tc 
o 

4 

POLES 

6 
POLES 

8 
POLES 

10 

POLES 

12 
POLES 

14 

POLES 

16 

POLES 

CONDUC" 

F 

E«TM^ 

B 

F 

RE- 
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B 

F 

RE- 

B 

F 

RE- 

ENTRANCY 

B 

F 

ENTRANCY 

B 

F 

RE- 
CNTRANC 

B 

F 

RE- 

EhTRANCY 

B 

0 
6 

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502 

ttB 

1ST 

(99) 

ut 

1-J7 

61 

(55) 

63 

31 

(55) 

31 

502 

504 

83 

S 

(55) 

88 

85 

51 

OOO 

51 

504 

506 

125 

127 

(9ft) 

1-J5 
129 

63 

(5s) 

65 

49 

(as) 

51 

31 

(55) 

33 

506 

508 

508 

510 

125 

13 

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12» 

9 

t<6 

cSS 

b5 

bt 

63 

ooo 

63 

! 

OOO 

QIS5 

43 
43 

35 

OOO 

37 

510 

512 

37 

(as) 

37 

512 

514 

m 
m 

(sa) 

121 
131 

65 

(55) 

65 

51 

(55) 

53 

514 

510 

85 
H7 

SvB 

3 

87 

51 

ooo 

51 

516 

518 

1-J7 
131 

(55) 

lift 

131 

63 

(55) 

65 

31 

(as) 

33 

518 

520 

520 

522 

1M 

131 

000 

ttl 

I-IH 

6? 

(55> 

87 
89 

65 

ooo 

67 

i 

S 

it 

38 

000 

33 

522 

521 

53 

(9A> 

53 

37 

(as) 

37 

524 

526 

i2« 
1  33 

(90) 

i 

65 

r?^ 

65 

51 

(SA> 

53 

37 

(98) 

39 

526 

528 

§5 

8ft? 

87 
b9 

528 

530 

131 
133 

r?tf) 

i 

67 

(5?) 

67 

530 

532 

532 

534 

131 
135 

000 

133 

135 

87 
89 

CC3 

OJJO 

8 

65 

ooo 

67 

53 

000 

55 

i 

<VU'LU 

45 
« 

33 

000 

33 

534 

536 

53 

(90) 

53 

536 

538 

133 
136 

(6a) 

133 

PR 

67 

§1 

69 

37 

(asD 

39 

33 

(as) 

35 

538 

540 

• 

<Sfl) 

39 

000 

39 

540 

542 

133 
137 

(99) 

13> 

l.'iT 

67 

(98) 

67 

542 

544 

55 

(55) 

55 

544 

546 

i 

ooo 

135 

13V 

ft 

CG§ 

B 

H 

69 

ooo 

69 

53 

ooo 

55 

i 

OOQ 
CFa5 

45 
47 

546 

548 

548 

550 

130 
law 

(99) 

137 

m 

67 

^99) 

69 

33 

(55) 

35 

550 

552 

93 

Mfi 

I 

39 

000 

39 

552 

554 

137 
13tt 

(55) 

137 
141 

69 

(M) 

71 

55 

(55) 

57 

39 

(55) 

41 

35 

(as) 

35 

554 

556 

55 

(55) 

55 

556 

558 

g 

000 

13? 

• 

("88) 

H 

69 

000 

69 

o 

47 

gg 

47 
47 

558 

560 

560 

562 

i 

(as) 

1 

71 

C9J!) 

VJ 

5(32 

564 

• 

»6 

8JS 

43 
96 

57 

000 

57 

564 

566 

ffl 

(as) 

141 
143 

69 

Czs) 

7] 

55 

(as) 

57 

39 

(as) 

41 

35 

(55) 

35 

5I5G 

568 

41 

(98) 

41 

568 

57(1 

HI 
143 

oou 

145 

• 
• 

M?S 

R 

71 

ooo 

73 

47 
47 

^Ifo 

S 

35 

ooo 

37 

570 

572 

572 

574 

ill 

(55) 

143 
U5 

71 

(as) 

71 

57 

(2.0) 

69 

574 

57<) 

»7 

^BS) 

»7 

57 

ooo 

57 

57G 

578 

143 
145 

(as) 

1*3 

H7 

73 

SB) 

73 

578 

580 

41 

(90) 

41 

580 

582 

113 
H7 

ooo 

145 
147 

91 
'.',- 

raS 

H 

n 

71 

ooo 

73 

47 
«| 

8£§ 

i 

41 

ooo 

43 

35 

ooo 

37 

582 

68  t 

59 

(as) 

59 

584 

58G 

145 
147 

(as) 

n;> 

14V 

73 

(2S) 

75 

57 

(99) 

59 

37 

(55) 

37 

586 

588 

«7 

W 

CCJ3 

OOO 

V7 
99 

588 

590 

145 

Htf 

(99-) 

147 
14*) 

73 

(99) 

73 

500 

592 

592 

594 

no 

1  19 

000 

i 

97 
90 

(20 

W 
1D1 

75 

ooo 

75 

59 

000 

61 

i 

ig 

M 

u 

41 

ooo 

43 

594 

596 

59 

(2S) 

59 

43 

(55) 

43 

59(5 

598 
600 

H7 

(55) 

I 

73 

(55) 

75 

37 

(55) 

37 

508 

101 

C^i> 

I 

600 

4 

6 

8     . 

10 

12 

14 

16     1 

TABLE  OF  TWO-CIRCUIT,  TRIPLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

CO 
1C 
0 

4 
POLES 

6 

POLES 

8 

POLES 

10 

POLES 

12 
POLES 

14 

POLES 

16 

POLES 

CONDUC" 

F 

RE- 

ENTBANCY 

B 

F 

RC- 

ENTRANC1 

B 

F 

RE- 

B 

F 

RE- 

B 

F 

E  NTRANC 

B 

F 

RE- 
ENTRANC 

B 

F 

ENTHAUCY 

B 

o 

d 

Z 

602 

14V 
161 

(S> 

14V 
163 

75 

(92) 

77 

37 

(55) 

39 

002 

604 

61 

(55) 

61 

(i()4 

ooo 

148 

m 

000 

IM 

163 

|V'i 

otfo 

m 

7r, 

ooo 

75 

59 

ooo 

61 

B 

JrtftS 

I 

i;oc, 

111  IS 

' 

43 

(55) 

43 

608 

610 

it) 

us 

(2JD 

151 
155 

77 

(55) 

77 

43 

(5fi) 

45 

610 

61*2 

i 

(M) 

is 

612 

614 

in 

156 

(55) 

153 
156 

75 

(SD 

77 

61 

(9<f> 

63 

37 

(SD 

:i',) 

614 

616 

61 

(55) 

61 

616 

618 

163 
166 

ooo 

158 

157 

101 

H  . 

£S 

is 

77 

000 

79 

..i 

51 

as 

§1 

39 

ooo 

39 

618 

020 

620 

622 

622 

1ST 

(5<ft 

167 

77 

(W) 

77 

43 

(5ft) 

45 

021 

i 

$?& 

iwt 

1&5 

63 

ooo 

<;:; 

45 

ooo 

45 

624 

0-20 

166 

I 

(55) 

1&& 

169 

79 

(55) 

79 

61 

(5s) 

63 

626 

628 

028 

630 

165 

W* 

ooo 

167 

15tf 

1 

(58) 

n 

77 

ooo 

79 

i 

£ 

B 

39 

ooo 

;  :  Q 
632 

632 

634 

157 
169 

<w> 

167 
161 

79 

(55> 

81 

63 

(55) 

65 

39 

(55) 

41 

634 

636 

a 

?ftS 

*» 

63 

ooo 

63 

45 

ooo 

45 

636 

638 

IB 

161 

(55) 

159 
1ft] 

79 

(55) 

79 

15 

(W> 

47 

out 

640 

042 

1&9 
101 

ooo 

i~uu 
m 

H 

oVS 

?ffl 

81 

ooo 

81 

B 

'V'  .j 

S 

• 

042 

M  I 

65 

(55) 

65 

644 

646 

159 

163 

(M> 

I 

79 

(98) 

81 

63 

(551 

65 

39 

(55) 

41 

646 

648 

1% 

r»9) 

B 

048 

650 

161 
183 

O 

! 

81 

(981 

83 

45 

rflso 

47 

41 

(55) 

41 

650 

652 

47 

(991 

47 

052 

654 

101 

1«6 

ooo 

si 

I 

<jj;  o 

cfc 

3 

81 

ooo 

81 

65 

ooo 

67 

M 

ooo 
<A£> 

H 

054 

656 

05 

(9P) 

65 

656 

658 

i 

(55) 

168 
167 

83 

(2S) 

83 

658 

<;r,o 

i 

oVo 

u* 

660 

002 

163 

167 

(55) 

166 
167 

81 

(55) 

83 

41 

(55) 

41 

662 

664 

67 

(99) 

67 

47 

(99) 

47 

664 

666 

166 

167 

000 

165 
169 

109 

111 

C<f<f> 

i 

83 

ooo 

85 

65 

ooo 

67 

B 

ss 

H 

47 

000 

49 

41 

ooo 

43 

000 

668 

008 

670 

166 
169 

(5s) 

1(7 
168 

83 

(55) 

83 

670 

672 

ffl 

««s 

115 

672 

674 

i 

(55) 

I 

85 

&a) 

85 

67 

(fifi) 

69 

074 

676 

67 

(W) 

67 

070 

678 

i 

000 

ffl 

i 

SvJ 

113 
116 

83 

000 

85 

8? 

oVo 

B 

-IT 

000 

49 

41 

COO 

43 

078 

080 

49 

(5s) 

49 

080 

082 

169 
171 

(98) 

1«9 
1J3 

85 

C2S) 

87 

43 

(55) 

43 

082 

68.1 

i 

Cca) 

B 

69 

000 

69 

084 

08C, 

• 

(fliO 

i 

85 

(5JD 

85 

(17 

<M> 

69 

680 

088 

08S 

li'.M) 

1 

ooo 

in 

175 

i 

8K 

ffl 

87 

ooo 

87 

1? 

;•,';': 

B 

690 

692 

49 

r9ff) 

49 

692 

694 

i 

<Sa) 

i 

85 

(2fl) 

87 

69 

(98) 

71 

49 

(5s) 

51 

43 

(89) 

43 

694 

696 

!S^ 

oVo 

llil 

69 

ooo 

69 

696 

698 

| 

(as) 

i;: 

87 

(5?) 

89 

43 

(591 

45 

698 

700 

700 

4 

6 

8 

10 

12 

14 

16 

TABLE  OF  TWO-CIRCUIT,  TRIPLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

CONDUCTORS 

4 

POLES 

6 

POLES 

8 

'POLES 

10 

'POLES 

12 

POLES 

14 

POLES 

16 

POLES 

F 

ENTRANCV 

B 

F 

"RE- 

ENTRANO 

B 

F 

E«T"'»"CY 

B 

F 

ENTRANCV 

B 

F 

RE- 

B 

F 

RE- 
eNTHANCY 

B 

F 

RE- 

B 

0 
o 

z 

702 

ffl 

ooo 

ffl 

1 

(55) 

117 
119 

87 

OOO 

87 

& 

s 

B 

702 

704 

71 

(92) 

71 

704 

706 

i 

red) 

i 

89 

(ea) 

89 

69 

res) 

7i 

49 

<3a) 

61 

706 

708 

I 

8s§ 

m 

119 

51 

000 

51 

708 

710 

175 
179 

(55) 

ti& 

87 

(5s) 

89 

43 

(as) 

45 

710 

712 

712 

714 

Hi 

ooo 

ft' 

s 

§^?o 

i 

89 

000 

91 

71 

000 

73 

\\ 

crtfo 

i 

45 

000 

45 

714 

716 

71 

f5a) 

71 

716 

718 

ia 

red) 

E 

89 

rea) 

55 

718 

720 

119 

!•-•! 

fee) 

i 

51 

000 

51 

720 

722 

§ 

fee) 

179 

1-.; 

91 

fea) 

1=1 

51 

(22) 

53 

722 

724 

73 

(92) 

73 

724 

726 

i 

ooo 

484 

i 

8A§ 

121 
123 

89 

ooo 

91 

71 

ooo 

73 

59 
61 

S£§ 

i 

45 

ooo 

45 

726 

728 

728 

730 

i 

ree") 

I 

91 

foe) 

93 

45 

foe) 

47 

730 

732 

121 

l^ 

M^TJ 

BO 

123 

732 

734 

ffl 

(09) 

.IS 

91 

dD 

91 

73 

(98) 

75 

51 

(22) 

53 

734 

736 

73 

(55) 

73 

53 

(55) 

53 

736 

738 

{M 

186 

ooo 

155 
187 

BD 

123 

rea) 

IL.'  ; 
125 

93 

ooo 

93 

61 
61 

8B 

• 

63 

738 

740 

740 

742 

g 

fee) 

185 

Id? 

91 

fee) 

93 

45 

(55) 

47 

742 

744 

'125 

^ 

123 

125 

75 

ooo 

75 

744 

746 

8! 

(28) 

145 
189 

93 

(5a) 

95 

73 

(55) 

75 

47 

(99) 

47 

746 

748 

53 

(55) 

53 

748 

750 

B 

ooo 

IS 

1-23 

as 

1*J5 
127 

93 

ooo 

93 

61 
63 

SK 

! 

53 

ooo 

55 

750 

752 

752 

754 

167 
189 

(22) 

i 

95 

(ea) 

95 

75 

fijD 

77 

754 

756 

l-.'7 

ree) 

i 

75 

000 

75 

756 

758 

1ST 
1V1 

(55) 

i 

93 

fee) 

95 

47 

(5s) 

47 

758 

760 

760 

762 

1M 

a 

coo 

189 
193 

125 

127 

cop 
GiT> 

i 

95 

ooo 

97 

i 

sas 

i 

53 

ooo 

55 

47 

ooo 

49 

762 

764 

77 

rea) 

77 

55 

(99) 

55 

764 

766 
768 

10 

.__  I1.'- 

fee') 

191 
193 

95 

(92) 

95 

75 

(ea) 

77 

766 

lit 

&V3 

127 
12» 

7G8 

770 

191 
193 

(22) 

.«l 

97 

(as) 

97 

770 

772 

77?, 

774 

ffi 

ooo 

48! 

127 

'129 

raa) 

i 

95 

000 

97 

77 

ooo 

79 

i 

® 

8 

47 

ooo 

49 

774 

776 

77 

fee) 

77 

55 

(98) 

55 

776 

778 

i 

(as) 

SJ 

97 

fee) 

99 

55 

(95) 

57 

49 

(55) 

49 

778 

780 

129 

131 

5gj 

IB 

131 

780 

782 

ID" 

(28) 

(197 

97 

(98) 

97 

782 

784 

79 

real 

79 

784 

786 

195 
197 

000 

196 
"199 

i 

crtft5 

131 
133 

99 

ooo 

99 

77 

ooo 

79 

65 
65 

07^ 

65 

786 

788 

788 

790 

195 
19U 

(»?> 

197 
1P9 

97 

(eo) 

99 

66 

(551 

57 

49 

(55) 

49 

790 

792 

i 

(eel 

131 
133 

57 

ooo 

57 

792 

794 

197 
UW 

(22) 

197 
2<)1 

99 

(55) 

101 

79 

(aa) 

81 

49 

(22) 

51 

794 

758 

79 

(99) 

79 

796 

798 

JH 

m 

000 

199 
2(11 

m 

133 

°fio 
DS> 

133 
133 

99 

ooo 

99 

65 

cop 
CS3D 

R 

798 

800 

800 

4 

6 

8 

10 

12 

14 

16 

O7  TUX        ^ 

SI7IRSIT7] 


WINDING  TABLES   FOR  MULTIPLE-CIRCUIT,  SINGLE   WINDINGS 

FOR   DRUM   ARMATURES. 


MULTIPLE-CIRCUIT,  SINGLE  WINDINGS,  FOR    DRUM  ARMATURES. 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

No.  OF  CONDUCTORS 

4 

POLES 

6 

POLES 

8 
POLES 

10 
POLES 

12 

POLES 

14 

POLES 

16 

POLES 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

202 

49 

51 

33 

35 

25 

27 

19 

21 

15 

17 

13 

15 

11 

13 

202 

204 

49 

51 

88 

35 

25 

27 

19 

21 

15 

17 

13 

15 

11 

13 

204 

206 

51 

53 

33 

35 

25 

27 

19 

21 

17 

19 

13 

15 

11 

13 

206 

208 

51 

5:5 

33 

35 

26 

27 

19 

21 

17 

19 

13 

15 

11 

13 

208 

210 

51 

53 

33 

35 

26 

27 

19 

21 

17 

19 

13 

15 

13 

15 

210 

212 

51 

58 

35 

37 

25 

27 

21 

23 

17 

19 

15 

17 

13 

15 

212 

214 

53 

55 

35 

37 

25 

27 

21 

23 

17 

19 

15 

17 

13 

15 

214 

216 

53 

55 

35 

37 

25 

27 

21 

23 

17 

19 

15 

17 

13 

15 

216 

218 

53 

55 

35 

37 

27 

29 

21 

23 

17 

19 

15 

17 

13 

15 

218 

22i) 

53 

55 

35 

37 

27 

29 

21 

23 

17 

19 

15 

17 

13 

15 

220 

222 

55 

57 

35 

37 

27 

29 

21 

23 

17 

19 

15 

17 

13 

15 

222 

224 

r>r> 

57 

37 

39 

27 

29 

21 

23 

17 

19 

15 

17 

13 

15 

224 

226 

55 

57 

37 

39 

27 

29 

21 

23 

17 

19 

15 

17 

13 

15 

226 

228 

55 

57 

37 

39 

27 

29 

21 

23 

17 

19 

15 

17 

13 

15 

228 

230 

57 

59 

37 

39 

27 

29 

21 

23 

19 

21 

15 

17 

13 

15 

230 

232 

57 

59 

37 

39 

27 

29 

23 

25 

19 

21 

15 

17 

13 

15 

232 

234 

57 

59 

37 

39 

29 

31 

23 

25 

19 

21 

15 

17 

13 

15 

234 

236 

57 

59 

39 

41 

29 

31 

23 

25 

19 

21 

15 

17 

13 

15 

236 

238 

59 

61 

39 

41 

29 

31 

23 

25 

19 

21 

15 

17 

13 

15 

238 

240 

r>;i 

61 

39 

>    41 

29 

31 

23- 

25 

19 

2] 

17 

19 

18 

15 

240 

242 

59 

til 

39 

41 

29 

31 

23 

25 

19 

21 

17 

19 

15 

17 

242 

244 

59 

c,r 

55 

41 

29 

31 

23 

25 

19 

21 

17 

19 

15 

17 

244 

246 

61 

03" 

39 

41 

29 

31 

23 

25 

19 

21 

17 

19 

15 

17 

246 

24S 

m  : 

o:; 

41 

43 

29 

31 

23 

25 

19 

21 

17 

19 

15 

17 

248 

250 

61 

03 

41 

43 

:-',l 

33 

23 

25 

19 

21 

17 

19 

15 

17 

250 

252 

61 

63 

41 

43 

31 

33 

25 

27 

19 

21 

17 

19 

15 

17 

252 

254 

63 

65 

41 

43 

31 

33 

25 

27 

21 

23 

17 

19 

15 

17 

254 

256 

58 

65 

41 

43 

31 

33 

25 

27 

21 

23 

17 

19 

15 

17 

256 

258 

63 

65 

41 

43 

31 

33 

25 

27 

21 

23 

17 

19 

15 

17 

258 

260 

63 

65 

43 

45 

31 

33 

25 

27 

21 

23 

17 

19 

15 

17 

260 

262 

65 

67 

43 

45 

31 

33 

25 

27 

21 

23 

17 

19 

15 

17 

262 

264 

65 

67 

43 

45 

31 

33 

25 

27 

21 

23 

17 

19 

15 

17 

264 

266 

65 

67 

43 

45 

33 

35 

25 

27 

21 

23 

17 

19 

15 

17 

266 

268 

65 

67 

4)! 

45 

33 

35 

25 

27 

21 

23 

19 

21 

15 

17 

268 

270 

67 

69 

43 

45 

33 

35 

25 

27 

21 

23 

19 

21 

15 

17 

270 

272 

67 

39 

45 

47 

33 

35 

27 

29 

21 

23 

19 

21 

15 

17 

272 

274 

67 

69 

45 

47 

33 

35 

27 

29 

21 

23 

19 

21 

17 

19 

274 

276 

67 

69 

45 

47 

33 

35 

27 

29 

21 

23 

19 

21 

17 

19 

276 

278 

69 

71 

45 

47 

33 

35 

27 

29 

23 

25 

19 

21 

17 

19 

278 

280 

<;;» 

71 

45 

47 

33 

35 

27 

29 

23 

25 

19 

21 

17 

19 

280 

282 

69 

71 

45 

47 

35 

37 

27 

29 

23 

25 

19 

21 

17 

19 

282 

284 

69 

71 

47 

49 

35 

37 

27 

29 

23 

25 

19 

21 

17 

19 

284 

286 

71 

73 

47 

49 

35 

37 

27 

29 

23 

25 

19 

21 

17 

19 

286 

2SS 

71 

73 

47 

49 

35 

37 

27 

29 

23 

25 

19 

21 

17 

1!) 

288 

290 

71 

73 

47 

49 

35 

37 

27 

29 

23 

25 

1',) 

21 

17 

19 

290 

292 

71 

73 

47 

49 

35 

37 

29 

31 

23 

25 

19 

2] 

17 

19 

292 

294 

73 

75 

47 

49 

35 

37 

29 

31 

23 

25 

19 

21 

17 

19 

294 

296 

73 

75 

49 

51 

35 

37 

29 

31 

28 

25 

21 

23 

17 

19 

296 

298 

73 

75 

49 

51 

37 

39 

29 

31 

23 

25 

21 

23 

17 

19 

298 

300 

73 

75 

49 

51 

37 

39 

29 

31 

23 

25 

21 

23 

17 

19 

300 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute  magnitude 
of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  SINGLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES. 

No.  OF  CONDUCTORS 

4 

POLES 

6 

POLES 

8 
POLES 

10 

POLES 

12 

POLES 

14 
POLES 

16 
POLES 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

302 

75 

77 

49 

51 

37 

39 

29 

31 

25 

27 

21 

23 

17 

19 

302 

304 

75 

77 

49 

51 

37 

39 

29 

31 

25 

27 

21 

23 

17 

19 

304 

306 

7.-> 

77 

49 

51 

37 

39 

29 

31 

25 

27 

21 

2:! 

19 

21 

306 

308 

75 

77 

51 

53 

37 

39 

29 

31 

25 

27 

21 

23 

19 

21 

308 

310 

77 

79 

51 

53 

37 

35 

29 

31 

25 

27 

21 

2:i 

19 

21 

310 

312 

77 

7',) 

51 

53 

37 

39 

31 

33 

25 

27 

21 

2:! 

19 

21 

312 

314 

77 

79 

51 

53 

39 

41 

31 

33 

25 

27 

21 

28 

19 

21 

314 

316 

77 

79 

51 

53 

39 

41 

31 

33 

25 

27 

21 

23 

19 

21 

316 

318 

79 

81 

51 

53 

39 

41 

31 

33 

25 

27 

21 

23 

19 

21 

318 

;f2o 

79 

SI 

53 

55 

39 

41 

31 

33 

25 

27 

21 

23 

19 

21 

320 

322 

79 

81 

53 

55 

39 

41 

31 

m 

25 

27 

21 

23 

19 

21 

322 

324 

79 

SI 

58 

55 

39 

41 

31 

33 

25 

27 

23 

25 

19 

21 

324 

326 

81 

83 

53 

55 

39 

41 

31 

33 

27 

29 

23 

25 

19 

21 

326 

328 

81 

83 

53 

55 

39 

41 

31 

33 

27 

29 

23 

25 

19 

21 

328 

330 

81 

83 

53 

55 

41 

43 

31 

33 

27 

29 

23 

25 

19 

21 

330 

332 

81 

83 

55 

57 

41 

43 

33 

35 

27 

29 

23 

25 

19 

21 

332 

334 

83 

85 

55 

57 

41 

43 

33 

86 

27 

29 

23 

25 

19 

21 

334 

:;:«; 

83 

85 

55 

57 

41 

48 

33 

35 

27 

29 

23 

25 

19 

21 

336 

338 

83 

85 

55 

57 

41 

43 

33 

35 

27 

29 

23 

25 

21 

23 

338 

;J40 

83 

85 

55 

57 

41 

43 

33 

86 

27 

29 

23 

25 

21 

28 

340 

342 

85 

87 

55 

57 

41 

43 

33 

35 

27 

2!) 

23 

25 

21 

23 

342 

344 

85 

87 

57 

59 

41 

43 

33 

35 

27 

29 

23 

25 

21 

23 

344 

346 

85 

87 

57 

59 

43 

45 

33 

35 

27 

29 

23 

25 

21 

23 

346 

348 

85 

87 

57 

59 

43 

45 

33 

35 

27 

29 

23 

25 

21 

23 

348 

:J50 

87 

89 

57 

59 

43 

45 

33 

35 

29 

31 

23 

25 

21 

23 

350 

352 

87 

89 

57 

oil 

43 

45 

35 

37 

29 

31 

25 

27 

21 

23 

352 

354 

87 

80 

57 

59 

43 

45 

35 

37 

29 

31 

25 

27 

21 

23 

354 

:;.-,(  ; 

87 

89 

59 

61 

43 

45 

35 

87 

29 

31 

25 

27 

21 

23 

356 

358 

89 

91 

59 

61 

43 

45 

35 

37 

29 

31 

25 

27 

21 

23 

358 

360 

89 

91 

59 

61 

43 

45 

35 

37 

29 

31 

25 

27 

21 

23 

360 

362 

89 

91 

59 

61 

45 

47 

86 

37 

29 

31 

25 

27 

21 

23 

362 

364 

89 

91 

59 

61 

45 

47 

35 

37 

29 

31 

25 

27 

21 

23 

364 

366 

9] 

93 

59 

61 

45 

47 

35 

37 

29 

31 

25 

27 

21 

23 

366 

368 

91 

93 

61 

63 

45 

47 

35 

37 

29 

31 

25 

27 

21 

23 

368 

370 

91 

93 

61 

63 

45 

47 

35 

37 

29 

31 

25 

27 

23 

25 

370 

372 

91 

93 

61 

63 

45 

47 

37 

39 

29 

31 

25 

27 

23 

25 

372 

374 

93 

95 

61 

63 

45 

47 

37 

39 

31 

33 

25 

27 

23 

25 

374 

376 

93 

95 

61 

63 

45 

47 

37 

39 

31 

33 

25 

27 

23 

25 

376 

378 

93 

95 

61 

63 

47 

49 

37 

39 

31 

33 

25 

27 

23 

25 

378 

380 

93 

95 

63 

65 

47 

49 

37 

39 

31 

33 

27 

29 

23 

25 

380 

382 

95 

97 

63 

65 

47 

49 

37 

39 

31 

33 

27 

29 

23 

25 

382 

384 

95 

97 

63 

65 

47 

49 

37 

39 

31 

33 

27 

29 

23 

25 

384 

386 

95 

97 

63 

65 

47 

49 

37 

39 

31 

33 

27 

29 

23 

25 

386 

388 

95 

97 

63 

65 

47 

49 

37 

39 

31 

33 

27 

29 

23 

25 

388 

390 

97 

99 

63 

65 

47 

49 

37 

89 

31 

33 

27 

29 

23 

25 

390 

392 

97 

99 

65 

67 

47 

49 

39 

41 

31 

33 

27 

29 

23 

25 

392 

394 

97 

99 

65 

67 

49 

51 

39 

41 

31 

33 

27 

29 

23 

25 

394 

396 

97 

99 

65 

67 

49 

51 

39 

41 

31 

33 

27 

29 

23 

25 

39(1 

398 

99 

101 

65 

67 

49 

51 

39 

41 

33 

35 

27 

29 

23 

25 

398 

400 

99 

101 

65 

67 

49 

51 

39 

41 

33 

35 

27 

29 

23 

25 

400 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute  magnitude 
of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  SINGLE  WINDINGS,  FOR  DRUM  ARMATURES. 

w 

• 
o 

FRONT  AND  BACK  PITCHES 

No.  OF  CON  DOCTORS 

CONDUC1 

4 

POLES 

6 
POLES 

8 
POLES 

10 

POLES 

12 

POLES 

14 
POLES 

16 

POLES 

o 

o 

z 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

402 

99 

101 

65 

67 

49 

51 

39 

41 

33 

35 

27 

29 

25 

27 

402 

404 

99 

101 

67 

69 

49 

51 

3!) 

41 

33 

35 

27 

29 

25 

27 

404 

406 

101 

103 

07 

69 

49 

51 

39 

11 

33 

35 

27 

29 

25 

27 

406 

408 

101 

103 

67 

69 

49 

51 

39 

41 

33 

35 

29 

31 

25 

27 

40S 

410 

101 

103 

67 

69 

51 

53 

39 

41 

33 

35 

29 

31 

25 

27 

410 

412 

101 

103 

67 

69 

51 

53 

41 

43 

33 

35 

29 

31 

25 

27 

412 

414 

103 

105 

67 

69 

51 

53 

41 

43 

33 

35 

29 

31 

25 

27 

414 

416 

103 

105 

09 

71 

51 

53 

41 

43 

33 

35 

29 

31 

25 

27 

416 

418 

103 

105 

69 

71 

51 

53 

41 

43 

33 

35 

29 

31 

25 

27 

418 

420 

103 

105 

69 

71 

51 

53 

41 

43 

33 

35 

29 

31 

25 

27 

420 

422 

105 

107 

69 

71 

51 

53 

41 

43 

35 

37 

29 

31 

25 

27 

422 

424 

105 

107 

O'J 

71 

51 

53 

41 

43 

35 

37 

29 

31 

25 

27 

424 

426 

105 

107 

69 

71 

5:! 

55 

41 

43 

35 

37 

29 

31 

25 

27 

426 

428 

105 

107 

71 

73 

53 

55 

41 

43 

35 

37 

29 

31 

25 

27 

428 

430 

107 

109 

71 

73 

53 

55 

41 

43 

35 

37 

29 

31 

25 

27 

430 

432 

107 

109 

71 

73 

53 

55 

43 

45 

35 

37 

29 

31 

25 

27 

432 

434 

107 

109 

71 

73 

53 

55 

43 

45 

35 

37 

29 

31 

27 

29 

434 

436 

107 

109 

71 

73 

53 

55 

43 

45 

35 

37 

31 

33 

27 

29 

436 

438 

109 

111 

71 

73 

53 

55 

43 

45 

35 

37 

31 

33 

27 

29 

438 

440 

109 

111 

73 

75 

53 

55 

43 

45 

35 

37 

31 

33 

27 

29 

440 

442 

109 

111 

73 

75 

55 

57 

43 

45 

35 

37 

31 

33 

27 

29 

442 

444 

109 

111 

73 

75 

55 

57 

43 

45 

35 

37 

:-n 

33 

27 

29 

444 

446 

111 

113 

73 

75 

55 

57 

43 

45 

37 

39 

31 

33 

27 

29 

446 

448 

111 

113 

73 

75 

55 

57 

43 

45 

37 

39 

31 

33 

27 

29 

448 

450 

111 

113 

73 

75 

55 

57 

43 

45 

37 

39 

31 

33 

27 

29 

450 

452 

111 

113 

75 

77 

55 

57 

45 

47 

37 

39 

31 

33 

27 

29 

452 

454 

113 

115 

75 

77 

55 

57 

45 

47 

37 

39 

31 

33 

27 

29 

454 

456 

113 

115 

75 

77 

55 

57 

45 

47 

37 

39 

31 

33 

27 

29 

456 

458 

113 

115 

75 

77 

57 

5'.) 

45 

47 

37 

39 

31 

33 

27 

29 

458 

460 

113 

115 

75 

77 

57 

59 

45 

47 

37 

39 

31 

33 

27 

29 

460 

462 

115 

117 

75 

77 

57 

59 

45 

47 

37 

39 

31 

33 

27 

29 

462 

464 

115 

117 

77 

79 

57 

59 

45 

47 

37 

39 

33 

35 

27 

29 

464 

466 

115 

117 

77 

7!) 

57 

59 

45 

47 

37 

39 

33 

35 

29 

31 

466 

468 

115 

117 

77 

79 

57 

59 

45 

47 

37 

39 

33 

35 

29 

31 

468 

470 

117 

119 

77 

7'J 

57 

59 

45 

47 

39 

41 

33 

35 

29 

31 

470 

472 

117 

119 

77 

79 

57 

59 

47 

49 

89 

41 

33 

35 

29 

31 

472 

474 

117 

119 

77 

79 

59 

61 

47 

49 

39 

41 

33 

35 

29 

31 

474 

476 

117 

119 

79 

81 

59 

61 

47 

49 

39 

41 

33 

35 

29 

31 

476 

478 

119 

121 

79 

81 

59 

Gl 

47 

49 

39 

41 

33 

35 

29 

31 

478 

480 

11!) 

121 

79 

81 

59 

61 

47 

49 

39 

41 

33 

35 

29 

31 

480 

482 

119 

121 

79 

81 

59 

61 

47 

49 

39 

41 

33 

35 

29 

31 

482 

484 

119 

121 

79 

81 

5!) 

01 

47 

49 

39 

41 

33 

86 

29 

31 

484 

486 

121 

123 

79 

81 

59 

61 

47 

49 

39 

41 

33 

35 

29 

31 

486 

488 

121 

123 

81 

83 

59 

61 

47 

•1',) 

39 

41 

33 

35 

29 

31 

488 

490 

121 

123 

81 

83 

61 

63 

47 

49 

39 

41 

33 

35 

29 

31 

490 

492 

121 

123 

81 

83 

61 

63 

49 

51 

39 

41 

35 

37 

29 

31 

492 

494 

123 

125 

81 

83 

61 

63 

49 

51 

41 

43 

35 

37 

29 

31 

494 

496 

123 

125 

81 

83 

61 

63 

49 

51 

41 

43 

35 

37 

29 

31 

496 

498 

123 

125 

81 

83 

61 

63 

49 

51 

41 

43 

35 

37 

31 

33 

498 

500 

123 

125 

83 

85 

61 

63 

49 

51 

41 

43 

35 

37 

31 

33 

500 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute  magnitude 
of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  SINGLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

No.  OF  CONDUCTORS 

4 

POLES 

6 

POLES 

8 

POLES 

10 

POLES 

12 

POLES 

14 

POLES 

16 

POLES 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

502 

125 

127 

s:;i 

85 

61 

63 

49 

51 

41 

43 

35 

37 

31 

33 

502 

504 

125 

127 

83 

85 

61 

63 

49 

51 

41 

43 

35 

37 

31 

33 

504 

5(10 

125 

127 

83 

85 

63 

66 

49 

51 

41 

43 

35 

37 

31 

33 

506 

508 

125 

127 

83 

85 

63 

65 

49 

51 

41 

43 

35 

37 

31 

33 

508 

510 

127 

129 

83 

85 

63 

65 

49 

51 

41 

43 

35 

.87 

;-!i 

33 

510 

ni2 

127 

129 

85 

87 

63 

65 

51 

53 

41 

43 

35 

37 

31 

33 

512 

514 

127 

129 

85 

87 

63 

65 

51 

53 

41 

43 

35 

82 

31 

33 

514 

516 

127 

129 

85 

87 

63 

65 

51 

53 

41 

43 

35 

37 

31 

33 

516 

518 

1211 

131 

85 

87 

63 

65 

51 

53 

43 

45 

35 

37 

31 

33 

518 

520 

_1~29 

131 

85 

87 

63 

65 

51 

53 

43 

45 

37 

39 

31 

33 

520 

522 

121) 

131 

85 

87 

65 

67 

51 

53 

43 

45 

37 

39 

31 

33 

522 

524 

129 

131 

87 

89 

65 

67 

51 

53 

43 

45 

37 

39 

31 

33 

524 

526 

131 

133 

87 

89 

65 

67 

51 

53 

43 

45 

37 

39 

8J 

33 

526 

528 

131 

133 

87 

89 

65 

67 

51 

53 

43 

45 

37 

39 

31 

33 

528 

530 

131 

133 

87 

89 

65 

67 

51 

53 

43 

45 

37 

39 

33 

35 

530 

532 

131 

133 

87 

89 

65 

67 

53 

55 

43 

45 

37 

39 

33 

35 

532 

534 

133 

135 

87 

89 

65 

67 

53 

55 

43 

45 

o7 

gg 

33 

35 

534 

536 

133 

135 

89 

91 

65 

67 

53 

55 

•I.", 

45 

37 

39 

:::! 

35 

536 

538 

133 

135 

§9 

91 

67 

69 

53 

55 

43 

45 

37 

39 

38. 

35 

538 

540 

133 

135 

89 

91 

67 

69 

53 

55 

43 

45 

37 

39 

83 

35 

540 

542 

135 

137 

89 

91 

67 

69 

53 

55 

45 

47 

37 

39 

33 

35 

542 

544 

135 

137 

89 

91 

67 

69 

53 

55 

45 

47 

37 

_39  : 

33 

35 

544 

546 

135 

137 

89 

91 

67 

69 

53 

55 

45 

47 

37 

39 

33 

35 

546 

548 

135 

137 

91 

93 

67 

69 

53 

55 

45 

17 

39 

41 

33 

35 

548 

550 

137 

139 

91 

93 

07 

69 

53 

55 

45 

47 

39 

41 

33 

35 

550 

552 

137 

139 

91 

93 

R/J 

In 

55 

57 

45 

47 

39 

41 

gg 

35 

652 

554 

137 

139 

91 

93 

6" 

,  i 

55 

57 

45 

47 

39 

41 

33 

35 

554 

556 

137 

139 

91 

93 

69 

71 

55 

57 

45 

47 

39 

41 

33 

35 

556 

558 

139 

111 

91 

93 

69 

71 

55 

57 

45 

47 

89 

41 

33 

35 

558 

560 

139 

141 

93 

95 

69 

71 

55 

57 

45 

47 

39 

41 

33 

86 

560 

562 

139 

141 

93 

95 

69 

71 

55 

57 

45 

47 

39 

41 

35 

37 

562 

564 

139 

141 

93 

95 

69 

71 

55 

57 

45 

47 

39 

41 

35 

37 

564 

566 

141 

in 

93 

95 

69 

71 

55 

57 

47 

49 

39 

41 

35 

37 

566 

5IJS 

141 

143 

93 

95 

69 

71 

55 

57 

47 

49 

39 

41 

86 

37 

568 

570 

141 

143 

93 

95 

71 

73 

55 

57 

47 

49 

89 

41 

35 

37 

570 

572 

141 

143 

95 

97 

71 

73 

57 

59 

47 

49 

39 

-11 

3.-> 

37 

572 

574 

143 

145 

95 

97 

71 

73 

57 

59 

47 

49 

39 

41 

35 

37 

574 

576 

143 

145 

95 

97 

71 

73 

57 

59 

47 

49 

41 

43 

35 

37 

576 

578 

M:i 

145 

95 

97 

71 

73 

57 

59 

•17 

49 

41 

43 

35 

37 

578 

580 

143 

145 

95 

97 

71 

73 

57 

59 

47 

49 

41 

43 

35 

37 

580 

582 

145 

147 

95 

97 

71 

73 

57 

59 

47 

49 

•Jl 

43 

86 

37 

682 

5M 

145 

117 

97 

1)1) 

71 

73 

57 

59 

47 

49 

-11 

43 

35 

37 

584 

ggg 

145 

147 

97 

99 

73 

75 

57 

59 

47 

49 

41 

43 

35 

37 

586 

588 

145 

147 

97 

99 

73 

75 

57 

59 

-17 

49 

41 

43 

35 

37 

588 

C-!)() 

147 

149 

97 

99 

73 

75 

57 

69 

49 

51 

41 

43 

35 

37 

590 

592 

147 

Ml) 

97 

99 

73 

75 

59 

61 

49 

51 

41 

43 

35 

37 

592 

594 

147 

149 

97 

99 

73 

75 

59 

61 

49 

51 

41 

43 

37 

39 

594 

596 

147 

149 

99 

101 

73 

75 

59 

61 

49 

51 

41 

43 

37 

39 

596 

598 

149 

151 

99 

101 

73 

75 

59 

61 

49 

51 

11 

43 

37 

39 

598 

600 

149 

151 

99 

101 

73 

75 

59 

61 

49 

51 

41 

43 

37 

39 

600 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute  magnitude 
of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  SINGLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

No.  OF  CONDUCTORS 

4 

POLES 

6 
POLES 

8 

POLES 

10 

POLES 

12 

POLES 

14 
POLES 

16 

POLES 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

602 

149 

151 

99 

101 

75 

77 

59 

61 

49 

51 

41 

43 

37 

39 

602 

604 

149 

151 

99 

101 

75 

77 

59 

61 

49 

51 

43 

45 

37 

39 

604 

606 

101 

153 

99 

101 

75 

77 

59 

61 

49 

51 

43 

45 

37 

39 

60(i 

608 

151 

153 

101 

103 

75 

77 

59 

61 

49 

51 

43 

45 

37 

39 

608 

610 

151 

153 

101 

103 

75 

77 

59 

61 

49 

51 

43 

45 

37 

39 

610 

612 

151 

153 

101 

103 

75 

77 

61 

63 

49 

51 

43 

45 

37 

39 

612 

614 

153 

155 

101 

103 

75 

77 

61 

63 

51 

53 

43 

45 

37 

39 

614 

616 

153 

155 

101 

103 

76 

77 

61 

63 

51 

53 

43 

45 

37 

39 

616 

618 

153 

155 

101 

103 

77 

71) 

61 

63 

51 

53 

13 

45 

37 

39 

618 

620 

153 

155 

103 

105 

77 

79 

61 

63 

51 

53 

43 

45 

37 

39 

620 

622 

155 

157 

103 

105 

77 

79 

61 

63 

51 

53 

43 

45 

37 

39 

622 

624 

1  50 

157 

103 

105 

77 

79 

61 

63 

51 

53 

43 

45 

37 

39 

624 

626 

155 

157 

103 

105 

77 

79 

61 

63 

51 

53 

43 

45 

39 

41 

626 

628 

155 

157 

103 

105 

77 

79 

61 

63 

51 

53 

43 

45 

39 

41 

628 

630 

157 

159 

103 

105 

77 

711 

61 

63 

51 

53 

43 

45 

39 

41 

630 

632 

157 

159 

105 

107 

77 

79 

63 

65 

51 

53 

45 

47 

39 

41 

632 

634 

157 

159 

105 

107 

79 

81 

63 

65 

51 

53 

45 

47 

39 

41 

634 

636 

157 

151) 

105 

107 

7!) 

81 

63 

65 

51 

53 

45 

47 

39 

41 

636 

638 

159 

161 

105 

107 

79 

81 

63 

65 

53 

55 

45 

47 

3!) 

-11 

638 

640 

159 

161 

105 

107 

79 

81 

63 

65 

53 

55 

45 

47 

31) 

41 

640 

642 

169 

161 

105 

107 

71) 

81 

63 

65 

53 

55 

45 

•17 

39 

41 

642 

644 

159 

161 

ior 

109 

79 

81 

63 

65 

53 

55 

45 

47 

39 

41 

644 

646 

161 

163 

107 

109 

79 

81 

63 

65 

o:i 

55 

45 

47 

39 

41 

646 

CIS 

Ifi'l 

163 

107 

109 

79 

81 

63 

65 

53 

55 

45 

47 

39 

41 

648 

650 

161 

163 

Tor: 

109 

81 

83 

I  63 

65 

53 

55 

45 

47 

39 

41 

650 

652 

161 

163 

107 

109 

81 

83 

68 

67 

53 

55 

45 

47 

39 

41 

652 

654 

163 

165 

107 

109 

81 

83 

65 

67 

53 

55 

45 

47 

39 

41 

654 

656 

163 

165 

10!) 

111 

81 

83 

65 

67 

53 

55 

45 

47 

39 

41 

6JMi 

608 

163 

165 

109 

111 

SI 

83 

65 

67 

68 

55 

45 

47 

41 

43 

608 

660 

163 

165 

109 

111 

SI 

83 

65 

67 

53 

55 

47 

49 

41 

43 

600 

662 

165 

167 

109 

111 

jIH 

;  s;r 

65 

67 

55 

57 

47 

49 

41 

43 

662 

664 

165 

167 

109 

111 

81 

83 

65 

67 

55 

57 

47 

49 

41 

43 

664 

666 

165 

167 

109 

111 

83 

85 

65 

67 

55 

57 

47 

49 

41 

43 

666 

668 

165 

167 

111 

113 

83 

85 

65 

67 

55 

57 

47 

49 

41 

43 

668 

670 

167 

169_| 

111 

113 

S3 

85 

65 

67 

55 

57 

47 

49 

41 

43 

670 

672 

167 

169 

111 

113 

53 

85 

67 

69 

55 

57 

47 

49 

41 

43 

672 

674 

167 

169 

111 

113 

83 

85 

67 

69 

55 

57 

47 

49 

41 

43 

674 

676 

167 

169 

111 

113 

85 

85 

67 

69 

55 

57 

47 

49 

41 

43 

676 

678 

169 

171 

111 

113 

83 

§6 

67 

69 

66 

57 

47 

49 

41 

43 

678 

680 

169 

171 

113 

115 

83 

SB 

67 

69 

55 

57 

47 

49 

41 

43 

680 

682 

169 

171 

113 

115 

85 

87 

67 

69 

55 

57 

47 

49 

41 

43 

682 

684 

169 

171 

113 

115 

85 

87 

67 

69 

55 

57 

47 

49 

41 

43 

684 

686 

171 

173 

113 

115 

85 

87 

67 

69 

57 

59 

47 

49 

41 

43 

686 

688 

171 

173 

113 

115 

85 

87 

67 

69 

57 

59 

49 

51 

41 

43 

688 

690 

171 

173 

113 

115 

85 

87 

67 

69 

57 

59 

49 

51 

43 

45 

690 

692 

171 

173 

115 

117 

85 

87 

69 

71 

57 

69 

49 

51 

43 

45 

692 

694 

173 

175 

115 

117 

85 

87 

69 

71 

57 

59 

49 

51 

43 

45 

694 

696 

173 

175 

115 

117 

85 

87 

69 

71 

57 

59 

49 

51 

43 

45 

696 

698 

173 

175 

115 

117 

87 

89 

69 

71 

57 

59 

49 

51 

43 

45 

698 

700 

173 

175 

115 

117 

87 

89 

69 

71 

57 

59 

49 

51 

43 

45 

700 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute  magnitude 
of  average  pitch  may  be  varied  with  n  reasonable  limits. 

UKI7BRSIT7 


MULTIPLE-CIRCUIT,  SINGLE  WINDINGS,  FOR  DRUM  ARMATURES. 

CO 

• 
o 

FRONT  AND  BACK  PITCHES 

No.  OF  CON  DOCTORS 

CONDUC" 

4 

POLES 

6 

POLES 

8 

POLES 

10 

POLES 

12 

POLES 

14 

POLES 

16 
POLES 

O 
6 

z 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

702 

175 

177 

115 

117 

87 

89 

69 

71 

57 

59 

49 

51 

13 

45 

702 

704 

175 

177 

117 

119 

87 

89 

69 

71 

57 

59 

49 

51 

43 

45 

704 

700 

175 

177 

117 

119 

87 

89 

69 

71 

57 

59 

49 

51 

13 

45 

706 

708 

175 

177 

117 

119 

87 

89 

69 

71 

57 

59 

49 

51 

•13 

45 

708 

710 

177 

179 

117 

119 

8f 

89 

69 

71 

59 

61 

49 

51 

43 

45 

710 

712 

177 

179 

117 

119 

87 

89 

71 

73 

59 

61 

49 

51 

43 

45 

712 

714 

177 

179 

117 

119 

89 

91 

71 

73 

59 

61 

49 

51 

43 

45 

714 

716 

177 

179 

119 

121 

89 

91 

71 

73 

59 

61 

51 

53 

43 

45 

716 

718 

179 

181 

119 

121 

89 

91 

71 

73 

59 

61 

51 

53 

43 

45 

718 

720 

179 

181 

119 

121 

89 

91 

71 

73 

59 

61 

51 

53 

43 

45 

720 

722 

179 

181 

119 

121 

89 

91 

71 

73 

59 

61 

51 

53 

45 

47 

722 

724 

179 

181 

119 

121 

89 

91 

71 

73 

59 

61 

51 

53 

45 

47 

721 

720 

181 

183 

119 

121 

89 

91 

71 

73 

59 

61 

51 

53 

46 

47 

726 

728 

181 

183 

121 

123 

89 

91 

71 

73 

59 

61 

51 

53 

45 

47 

728 

730 

181 

183 

121 

123 

91 

93 

71 

73 

59 

61 

51 

53 

45 

47 

73(1 

732 

181 

183 

121 

1  23 

91 

93 

73 

75 

59 

61 

51 

53 

45 

47 

732 

734 

183 

185  • 

121 

12:', 

91 

93 

73 

75 

61 

68 

51 

53 

45 

47 

734 

736 

183 

185 

121 

123 

91 

93 

73 

75 

61 

63 

51 

53 

45 

47 

736 

738 

183 

185 

121 

123 

91 

93 

73 

75 

61 

68 

51 

53 

45 

47 

738 

740 

183 

185 

123 

125 

91 

93 

73 

75 

61 

68 

51 

53 

45 

47 

740 

742 

185 

187 

123 

125 

91 

93 

73 

75 

61 

03 

51 

53 

45 

47 

742 

_744 

185 

187 

123 

125 

91 

93 

73 

75 

61 

63 

53 

55 

45 

47 

744 

746 

185 

187 

123 

125 

93 

95 

73 

75 

61 

63 

53 

55    . 

45 

47 

740 

748 

isr,  . 

187 

123 

125 

93 

95 

73 

75 

61 

63 

53 

55 

45 

47 

748 

750 

187 

189 

123 

125 

93 

95 

73 

75 

61 

63 

53 

65 

45 

47 

750 

752 

187 

189 

125 

127 

93 

95 

75 

77 

61 

03 

53 

55 

45 

47 

752 

754 

187 

189 

125 

127 

93 

95 

75 

77 

61 

68 

53 

55 

47 

49 

754 

756 

187 

189 

125 

127 

93 

95 

•    75 

77 

(il 

63 

53 

55 

47 

49 

756 

758 

189 

191 

125 

127 

93 

95 

75 

77 

63 

65 

53 

55 

47 

49 

758 

760 

189 

191 

125 

127 

93 

95 

75 

77 

63 

65 

53 

55 

47 

49 

700 

762 

189 

191 

125 

127 

95 

97 

75 

77 

63 

65 

53 

55 

47 

49 

762 

764 

189 

191 

127 

1  29 

95 

97 

75 

77 

63 

65 

53 

55 

47 

49 

764 

766 

191 

193 

127 

129 

95 

97 

75 

77 

63 

65 

53 

55 

47 

49 

766 

768 

191 

193 

127 

129 

95 

97 

75 

77 

63 

65 

53 

55 

47 

49 

708 

770 

191 

193 

127 

129 

95 

97 

75 

77 

63 

65 

53 

55 

47 

49 

770 

772 

191 

193 

127 

129 

95 

97 

77 

79 

63 

65 

55 

57 

47 

49 

772 

774 

193 

195 

127 

129 

95 

97 

77 

79 

63 

65 

55 

57 

47 

49 

774 

776 

193 

195 

129 

131 

95 

97 

77 

79 

63 

65 

55 

57 

47 

49 

776 

778 

193 

195 

129 

131 

97 

99 

77 

79 

63 

65 

55 

57 

47 

49 

778 

780 

193 

195 

129 

131 

97 

99 

77 

79 

63 

65 

55 

57 

47 

49 

780 

782 

195 

197 

129 

131 

97 

99 

77 

79 

65 

67 

55 

57 

47 

49 

782 

784 

195 

197 

129 

131 

97 

99 

77 

79 

65 

67 

55 

57 

47 

49 

784 

__780 

195 

197 

129 

131 

97 

99 

77 

79 

65 

67 

55 

57 

49 

51 

786 

788 

195 

197 

131 

133 

97 

99 

77 

79 

65 

67 

55 

57 

49 

51 

788 

790 

197 

199 

131 

133 

97 

99 

77 

79 

65 

67 

55 

57 

49 

51 

790 

792 

197 

199 

131 

133 

<J7 

99 

79 

81 

65 

07 

55 

57 

49 

51 

792 

794 

197 

199 

131 

133 

99 

101 

79 

81 

65 

07 

55 

57 

49 

51 

794 

796 

197 

199 

131 

133 

99 

101 

79 

81 

65 

67 

55 

57 

49 

51 

796 

798 

199 

•2D1 

131 

133 

99 

101 

79 

81 

65 

67 

55 

57 

49 

51 

798 

800 

199 

201 

133 

135 

99 

101 

79 

81 

65 

67 

57 

59 

49 

51 

800 

Above  choice  of  Pitches  will  prove  mos-fc  satisfactory,  although,  as  stated  in  text,  the  absolute  magnitude 
of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT  SINGLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

CO 
EC 
O 

4 

POLES 

6 

POLES 

8 

POLES 

10 

POLES 

12 
POLES 

14 

POLES 

16 

POLES 

O 

O 
Q 

Z 

o 
o 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

0 

6 

Z 

802 

199 

201 

133 

135 

99 

101 

79 

81 

65 

67 

57 

59 

49 

51 

802 

804 

199 

201 

133 

135 

99 

101 

79 

81 

65 

67 

57 

59 

49 

51 

804 

806 

201 

203 

133 

135 

99 

101 

79 

81 

67 

69 

57 

59 

49 

51 

806 

808 

201 

203 

133 

135 

99 

101 

79 

81 

67 

69 

57 

59 

49 

51 

808 

810 

201 

203 

133 

135 

101 

103 

79 

81 

67 

69 

57 

59 

49 

51 

810 

812 

201 

203 

135 

137 

101 

103 

81 

83 

67 

69 

57 

59 

49 

51 

812 

814 

203 

205 

135 

137 

101 

103 

81 

83 

67 

69 

57 

59 

49 

51 

814 

816 

203 

205 

135 

137 

101 

103 

81 

83 

67 

69 

57 

59 

49 

51 

816 

818 

203 

205 

135 

137 

101 

103 

81 

83 

67 

69 

57 

59 

51 

53 

818 

820 

203 

205 

135 

137 

101 

103 

81 

83 

67 

GO 

57 

59 

51 

53 

820 

822 

205 

207 

135 

137 

101 

103 

81 

83 

67 

69 

57 

59 

51 

53 

822 

824 

205 

207 

137 

139 

101 

103 

81 

83 

67 

69 

57 

59 

51 

53 

824 

826 

205 

207 

137 

139 

103 

105 

81 

83 

67 

69 

57 

59 

51 

53 

826 

828 

205 

207 

137 

139 

103 

105 

81 

83 

67 

69 

59 

61 

51 

53 

828 

830 

207 

209 

137 

139 

103 

105 

81 

83 

69 

71 

59 

61 

51 

53 

830 

832 

207 

209 

137 

139 

103 

105 

83 

85 

69 

71 

59 

61 

51 

53 

832 

834 

207 

209 

137 

139 

103 

105 

83 

85 

69 

71 

59 

61 

51 

53 

834 

836 

207 

209 

139 

141 

103 

105 

83 

85 

69 

71 

59 

61 

51 

53 

836 

838 

209 

211 

139 

141 

103 

105 

83 

85 

69 

71 

59 

61 

51 

53 

838 

840 

209 

211 

139 

141 

103 

105 

83 

85 

69 

71 

59 

61 

51 

53 

840 

842 

209 

211 

139 

141 

105 

107 

83 

85 

69 

71 

59 

61 

51 

53 

842 

844 

209 

211 

139 

141 

105 

107 

83 

85 

69 

71 

59 

61 

51 

53 

844 

846 

211 

213 

139 

141 

105 

107 

83 

85 

69 

71 

59 

61 

51 

53 

846 

_818  . 

211 

213 

141 

143 

105 

107 

83 

85 

69 

71 

59 

61 

51 

53 

848 

850 

211 

213 

141 

143 

105 

107 

83 

85 

69 

71 

59 

61 

53 

55 

850 

852 

211 

213 

141 

143 

105 

107 

85 

87 

69 

71 

59 

61 

53 

55 

852 

854 

213 

215 

14; 

143 

105 

107 

85 

87 

71 

73 

59 

61 

53 

55 

854 

856 

213 

215 

141 

143 

105 

107 

85 

87 

71 

73 

61 

63 

53 

55 

856 

S58 

213 

215 

141 

143 

107 

109 

85 

87 

71 

73 

61 

63 

53 

55 

858 

860 

213 

215 

143 

145 

107 

109 

85 

87 

71 

73 

61 

63 

53 

55 

860 

802 

215 

217 

143 

145 

107 

109 

85 

87 

71 

73 

61 

63 

53 

55 

862 

864 

215 

217 

143 

145 

107 

109 

85 

87 

71 

73 

61 

63 

53 

55 

864 

866 

215 

217 

143 

145 

107 

109 

85 

87 

71 

73 

61 

63 

53 

55 

866 

8G8 

215 

217 

143 

145 

107 

109 

85 

87 

71 

73 

61 

63 

53 

55 

868 

870 

217 

219 

143 

145 

107 

109 

85 

87 

71 

73 

61 

63 

53 

55 

870 

872 

217 

219 

145 

147 

107 

109 

87 

89 

71 

73 

61 

63 

53 

55 

872 

874 

217 

219 

145 

147 

109 

111 

87 

89 

71 

73 

61 

63 

53 

55 

874 

876 

217 

219 

145 

147 

109 

111 

87 

89 

71 

73 

61 

63 

53 

55 

876 

878 

219 

221 

145 

147 

109 

111 

87 

89 

73 

75 

61 

63 

53 

55 

878 

880 

219 

221 

145 

147 

109 

111 

87 

89 

73 

75 

61 

63 

53 

55 

880 

882 

219 

221 

145 

147 

109 

111 

87 

89 

73 

75 

61 

63 

55 

57 

882 

884 

219 

221 

147 

149 

109 

111 

87 

89 

73 

75 

68 

65 

55 

57 

884 

.880  ; 

221 

223 

147 

149 

109 

111 

87 

89 

73 

75 

6§ 

65 

55 

57 

886 

888 

221 

223 

147 

149 

109 

111 

87 

89 

73 

75 

63 

65 

55 

57 

888 

890 

221 

223 

147 

149 

111 

113 

87 

89 

73 

75 

63 

65 

55 

57 

890 

892 

221 

223 

147 

149 

111 

113 

89 

91 

73 

75 

63 

65 

55 

57 

892 

894 

223 

225 

147 

149 

111 

11H 

8!) 

91 

73 

75 

63 

65 

55 

57 

894 

896 

223 

225 

149 

151 

111 

113 

89 

91 

73 

75 

63 

65 

55 

57 

896 

898 

223 

225 

149 

151 

111 

113 

89 

91 

73 

75 

63 

65 

55 

57 

898 

900 

223 

225 

149 

151 

111 

113 

8'.) 

91 

73 

75 

63 

65 

55 

57 

900 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute  magnitude 
of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  SINGLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

CO 

K 

O 

(- 

4 

POLES 

6 

POLES 

8 
POLES 

10 

POLES 

12 

POLES 

14 

POLES 

16 

POLES 

o 

u 

0 

z 

0 

o 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

o 

0 

z 

902 

225 

227 

149 

151 

in 

113 

89 

91 

75 

77 

63 

65 

55 

57 

902 

904 

225 

227 

149 

151 

in 

113 

89 

91 

75 

77 

63 

65 

55 

57 

904 

906 

225 

227 

149 

151 

113 

115 

89 

91 

75 

77 

63 

65 

55 

57 

906 

908 

225 

227 

151 

153 

113 

115 

81) 

91 

75 

77 

63 

65 

55 

57 

908 

910 

227 

229 

K>] 

153 

113 

115 

8!) 

91 

75 

77 

63 

65 

55 

57 

910 

912 

227 

229 

151 

153 

113 

115 

91 

93 

75 

77 

65 

67 

55 

57 

932 

914 

227 

229 

151 

153 

113 

115 

91 

93 

75 

77 

65 

67 

57 

69 

914 

916 

'2-27 

229 

151 

lf,3 

113 

115 

91 

93 

75 

77 

65 

67 

57 

69 

916 

918 

229 

231 

151 

153 

113 

115 

91 

93 

75 

77 

65 

67 

57 

59 

918 

920 

229 

231 

153 

155 

113 

115 

91 

93 

75 

77 

65 

67 

57 

59 

920 

922 

229 

231 

153 

155 

115 

117 

91 

93 

75 

77 

65 

67 

57 

59 

922 

924 

229 

231 

153 

155 

115 

117 

91 

93 

75 

77 

65 

67 

57 

59 

924 

926 

231 

'233 

153 

155 

115 

117 

91 

93 

77 

79 

65 

67 

57 

69 

926 

928 

231 

233 

153 

155 

115 

117 

91 

93 

77 

79 

65 

67 

57 

59 

928 

930 

231 

233 

153 

155 

115 

117 

91 

93 

77 

79 

65 

67 

57 

65 

930 

932 

231 

233 

155 

157 

115 

117 

93 

95 

77 

79 

65 

67 

57 

59 

932 

934 

233 

235 

155 

157 

115 

117 

93 

95 

77 

79 

65 

67 

57 

59 

1)34 

936 

233 

235 

155 

157 

115 

117 

93 

95 

77 

79 

65 

67 

57 

59 

936 

938 

233 

235 

155 

157 

117 

119 

93 

95 

77 

79 

65 

67 

57 

59 

938 

940 

233 

235 

155 

157 

117 

119 

93 

95 

77 

79 

67 

69 

57 

59 

940 

942 

235 

237 

155 

157 

117 

119 

93 

95 

77 

79 

67 

69 

57 

59 

942 

944 

235 

237 

157 

159 

117 

119 

93 

95 

77 

79 

67 

69 

57 

59 

944 

946 

235 

237 

157 

159 

117 

119 

93 

95 

77 

79 

67 

69 

59 

01 

946 

948 

235 

237 

157 

159 

117 

119 

93 

95 

77 

79 

67 

69 

59 

01 

948 

950 

237 

239 

157 

159 

117 

]  1  '.) 

93 

95 

79 

81 

67 

69 

59 

61 

950 

952 

237 

23!)    j 

157 

159 

117 

119 

95 

97 

79 

81 

07 

69 

59 

61 

952 

954 

237 

239 

157 

159 

119 

121 

95 

97 

79 

81 

67 

69 

59 

61 

954 

956 

237 

239 

159 

161 

119 

121 

95 

97 

79 

81 

67 

0!) 

59 

61 

956 

958 

239 

241 

159 

161 

119 

121 

95 

97 

79 

81 

67 

0!) 

59 

01 

958 

960 

239 

241 

159 

161 

119 

121 

96 

97 

79 

81 

67 

69 

59 

01 

960 

962 

239 

241 

159 

101 

119 

121 

95 

97 

79 

81 

67 

69 

59 

61 

962 

964 

239 

241 

159 

161 

119 

121 

95 

97 

79 

81 

67 

69 

59 

61 

964 

966 

241 

243 

159 

161 

119 

121 

95 

97 

79 

81 

67 

69 

59 

61 

966 

968 

241 

243 

IB; 

163 

119 

121 

95 

97 

79 

81 

69 

71 

59 

61 

968 

970 

241 

243 

161 

163 

121 

123 

95 

97 

79 

81 

69 

71 

59 

61 

970 

972 

241 

243 

161 

163 

121 

123 

97 

99 

79 

81 

69 

71 

59 

61 

972 

974 

243 

245 

161 

163 

121 

123 

97 

99 

81 

83 

69 

71 

59 

61 

974 

976 

243 

245 

161 

163 

121 

123 

97 

99 

81 

83 

69 

71 

59 

61 

976 

978 

243 

245 

161 

163 

121 

123 

97 

99 

81 

83 

69 

71 

61 

63 

978 

980 

243 

245 

163 

165 

121 

123 

97 

99 

81 

83 

69 

71 

61 

03 

98(1 

982 

_245 

247 

163 

165 

121 

123 

97 

99 

81 

83 

69 

71 

61 

03 

982 

984 

245 

247 

163 

165 

121 

123 

97 

99 

81 

83 

69 

71 

61 

63 

984 

986 

245 

247 

163 

165 

123 

125 

97 

99 

81 

83 

69 

71 

61 

63 

986 

988 

245 

247 

163 

165 

123 

125 

97 

99 

81 

83 

69 

71 

61 

63 

988 

990 

247 

24!) 

163 

165 

123 

125 

97 

99 

81 

83 

69 

71 

61 

63 

990 

992 

247 

249 

165 

167 

123 

125 

99 

101 

81 

83 

69 

71 

61 

63 

992 

994 

247 

249 

165 

167 

123 

125 

99 

101 

81 

83 

69 

71 

61 

63 

994 

996 

247 

249 

165 

167 

123 

125 

99 

101 

81 

83 

71 

73 

61 

63 

990 

998 

249 

251 

165 

167 

123 

125 

99 

101 

83 

85 

71 

73 

61 

63 

998 

1000 

249 

251 

165 

107 

123 

125 

99 

101 

83 

85 

71 

73 

61 

63 

1000 

Above  choice  of  Pitches  wfll  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute  magnitude 
of  average  pltcb  may  be  varied  within  reasonable  thrifts. 

MULTIPLE  CIRCUIT,  SINGLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.  OFCONDUCTORS 

FRONT  AND  BACK  PITCHES 

No.  OFCONDUCTORS 

4 

POLES 

6 

POLES 

8 

POLES 

10 

POLES 

12 

POLES 

14 

POLES 

16 
POLES 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

1002 

249 

251 

165 

167 

125 

127 

99 

101 

83 

85 

71 

73 

61 

63 

1002 

1004 

249 

251 

167_ 

169 

125 

127 

99 

101 

83 

85 

71 

73 

61 

63 

1004 

100(5 

251 

253 

107 

169 

m 

127 

99 

101 

83 

85 

71 

73 

61 

63 

1006 

1008 

251 

253 

167 

169 

125 

127 

99 

101 

83 

85 

71 

73 

61 

63 

1008 

1010 

251 

253 

167 

169 

125 

127 

99 

101 

83 

85 

71 

73 

63 

65 

1010 

1012 

251 

253 

167 

169 

125 

127 

101 

103 

83 

85 

71 

.    73 

63 

65 

1012 

1014 

253 

255 

167 

169 

125 

127 

101 

103 

83 

85 

71 

73 

63 

65 

1014 

1016 

253 

255 

169 

171 

125 

127 

101 

103 

83 

85 

71 

73 

63 

65 

1016 

1018 

253 

255 

169 

171 

127 

129 

101 

103 

83 

85 

71 

73 

63 

65 

1018 

1020 

253 

255 

169 

171 

127 

129 

101 

103 

83 

85 

71 

73 

63 

65 

1020 

1022 

255 

257 

169 

171 

127 

129 

101 

103 

85 

87 

71 

7:1 

63 

65 

1022 

1024 

255 

257 

169 

171 

127 

129 

101 

103 

85 

87 

73 

75 

63 

65 

1024 

1026 

255 

257 

169 

171 

127 

129 

101 

103 

85 

87 

73 

75 

63 

65 

1026 

1028 

255 

257 

171 

173 

127 

129 

101 

103 

85 

87 

73 

75 

63 

65 

1028 

1030 

257 

259 

171 

173 

127 

129 

101 

103 

85 

87 

73 

75 

63 

65 

1030 

1032 

257 

259 

171 

173 

127 

129 

103 

105 

85 

87 

73 

75 

63 

65 

1032 

1034 

257 

259 

171 

173 

129 

18J 

103 

105 

85 

87 

73 

75 

63 

65 

1034 

1_036 

257 

259 

171 

173 

129 

131 

103 

105 

85 

87 

73 

75 

63 

65 

1036 

1038_j 

259 

261 

171 

173 

129 

131 

103 

105 

85 

87 

73 

75 

63 

65 

1038 

1040 

259 

2lU 

173 

175 

129 

131 

103 

105 

85 

87 

73 

75 

63 

65 

1040 

10-12 

259 

261 

173 

175 

129 

131 

103 

105 

85 

87 

73 

75 

65 

07 

1042 

1044 

259 

2<>1 

178  J 

175 

129 

131 

103 

105 

85 

87 

73 

75 

65 

67 

1044 

104(3 

261 

263 

173 

175 

129 

131 

103 

105 

87 

89 

73 

75 

65 

67 

1046 

1048 

261 

263 

173 

175 

129 

131 

103 

105 

87 

89 

73 

75 

65 

67 

1048 

1  050 

261 

263 

173 

175 

131 

133 

103 

105 

87 

89 

73 

75 

65 

67 

1050 

1052 

261 

263 

175 

177 

131 

133 

105 

107 

87 

89 

75 

77 

65 

67 

1052 

1054 

263 

265 

175 

177 

131 

133 

105 

107 

§7 

89 

75 

77 

65 

67 

1054 

1056 

263 

265 

175 

177 

131 

133 

105 

107 

87 

89 

75 

77 

65 

67 

1056 

_1058_ 

263 

265 

175 

177 

"13.1  I 

133 

105 

107 

87 

89 

75 

77 

65 

67 

1058 

101)0 

263 

265 

175 

177 

131 

133 

105 

107 

87 

89 

75 

77 

65 

67 

ioi;o 

1062 

265 

267 

175 

177 

131 

133 

105 

107 

87 

89 

75 

77 

65 

67 

1062 

1064 

265 

267 

177 

179 

131 

133 

105 

107 

87 

89 

75 

77 

65 

67 

1064 

1066 

265 

267 

177 

179 

133 

135 

105 

107 

87 

89 

75 

77 

65 

67 

1066 

1068 

265 

267 

177 

179 

133 

135 

105 

107 

87 

89 

75 

77 

66 

67 

1068 

1070 

267 

269 

177 

1  79 

188 

185 

105 

107 

89 

1)1 

75 

77 

(55 

67 

1070 

1072 

267 

269 

177 

179 

133 

135 

107 

109 

89 

91 

75 

77 

66 

67 

1072 

1074 

267 

269 

177 

179 

133 

135 

107 

109 

89 

91 

75 

77 

67 

I','.) 

1074 

1070 

267 

269 

179 

181 

133 

135 

107 

109 

89 

91 

75 

77 

67 

69 

107(1 

1078 

269 

271 

179 

181 

133 

135 

107 

109 

89 

91 

75 

77 

67 

69 

1078 

1080 

269 

271 

179 

181 

133 

135 

107 

109 

89 

91 

77 

79 

67 

69 

1080 

1082 

269 

271 

179 

181 

135 

137 

107 

109 

89 

91 

77 

79 

67 

69 

1082 

1084 

269 

271 

179 

181 

135 

137 

107 

109 

89 

91 

77 

79 

67 

<;'.) 

1084 

1086 

271 

273 

17!) 

181 

135 

137 

107 

109 

89 

91 

77 

79 

67 

69 

1086 

1088 

271 

273 

LSI 

183 

135 

137 

107 

109 

89 

91 

77 

79 

67 

69 

1088 

1090 

271 

273 

181 

183 

186 

137 

107 

109 

89 

91 

77 

7!» 

67 

69 

1090 

1092 

271 

27:) 

181 

183 

135 

137 

109 

111 

89 

91 

77 

79 

67 

69 

1092 

1094 

273 

275 

181 

183 

135 

137 

109 

111 

91 

93 

77 

79 

67 

69 

1094 

1096 

273 

275 

1.81 

183 

135 

137 

109 

111 

91 

93 

77 

79 

67 

69 

1096 

10!>8_[ 

273 

275 

181 

183 

137 

139 

109 

111 

91 

93 

77 

7!) 

67 

69 

1098 

1100 

273 

275 

183 

185 

137 

139 

109 

111 

91 

93 

77 

7',) 

67 

69 

1100 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute  magnitude 
of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  SINGLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

CO 
DC 
O 

4 

POLES 

6 

POLES 

8 

POLES 

10 
POLES 

12 

POLES 

14 
POLES 

16 

POLES 

o 

3 

0 

z 

0 

o 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

o 

o 

z 

1102 

275 

277 

183 

185 

137 

139 

109 

111 

91 

93 

77 

79 

67 

69 

1102 

1104 

•i-:> 

277 

183 

185 

137 

139 

109 

111 

91 

93 

77 

79 

67 

69 

1104 

1106 

275 

277 

183 

185 

137 

139 

109 

111 

91 

93 

77 

79 

69 

71 

1106 

1108 

275 

277 

183 

185 

137 

139 

109 

111 

91 

93 

79 

81 

69 

71 

1108 

1110 

277 

279 

183 

185 

137 

139 

109 

111 

91 

93 

79 

81 

69 

71 

1110 

1112 

•J77 

279 

185 

187 

137 

139 

111 

113 

91 

93 

79 

81 

69 

71 

1112 

1114 

277 

279 

185 

187 

139 

141 

111 

113 

91 

93 

79 

81 

69 

71 

1114 

1J1  6 

277 

279 

185 

187 

139 

141 

111 

113 

91 

93 

79 

81 

68 

71 

1116 

1118 

279 

281 

185 

187 

139 

141 

111 

113 

93 

95 

79 

81 

69 

71 

1118 

1120 

279 

281 

185 

187 

139 

141 

111 

113 

93 

95 

79 

81 

69 

71 

1120 

1122 

279 

281 

185 

187 

139 

141 

111 

113 

93 

95 

79 

81 

69 

71 

1122 

1124 

279 

281 

187 

189 

139 

141 

111 

113 

93 

95 

79 

81 

69 

71 

1124 

1126 

281 

283 

187 

189 

139 

141 

111 

113 

93 

95 

79 

81 

69 

71 

1126 

1128 

281 

283 

1S7 

189 

139 

141 

111 

113 

93 

95 

79 

81 

69 

71 

1128 

1130 

281 

283 

187 

189 

141 

143 

111 

113 

93 

95 

79 

81 

69 

71 

1130 

1132 

281 

283 

187 

189 

141 

143 

113 

115 

93 

95 

79 

81 

69 

71 

11  32 

1134 

2S3 

285 

187 

189 

141 

143 

113 

115 

93 

95 

79 

81 

69 

71 

1184 

1136 

283 

285 

189 

191 

141 

143 

113 

115 

93 

95 

81 

83 

69 

71 

1136 

1138 

283 

285 

189 

191 

141 

143 

113 

115 

93 

95 

81 

83 

71 

73 

1138 

1140 

283 

285 

189 

191 

1  11 

143 

113 

115 

93 

95 

81 

83 

71 

73 

1140 

111:2 

285 

287 

189 

191 

141 

113 

113 

115 

95 

97 

SI 

83 

71 

73 

114.2 

1111 

285 

287 

189 

191 

141 

143 

113 

115 

95 

97 

81 

83 

71 

73 

1144 

1146 

285 

287 

189 

191 

1  13 

145 

113 

115 

95 

97 

81 

83 

71 

73 

1146 

HIS 

285 

287 

191 

193 

143 

145 

113 

115 

95 

97 

81 

S3 

71 

73 

1148 

1.150 

287 

289 

191 

193 

143 

145 

113 

115 

95 

97 

81 

83 

71 

73 

1150 

1152 

li-Si 

289 

191 

193 

143 

145 

115 

117 

95 

97 

81 

83 

71 

73 

1152 

1151 

287 

2S9 

191 

193 

143 

145 

115 

117 

95 

97 

81 

83 

71 

73 

1  1  54 

1156 

287 

289 

191 

193 

143 

145 

115 

117 

95 

97 

81 

83 

71 

73 

1  1  56 

1158 

289 

291 

191 

193 

1  13 

145 

115 

117 

95 

97 

SI 

83 

71 

73 

1  1  58 

1160 

289 

291 

193 

195 

143 

145 

115 

117 

95 

97 

81 

83 

71 

73 

1160 

1.162 

289 

291 

193 

195 

1  15 

m 

115 

117 

95 

97 

81 

S3 

71 

73 

1~162 

lli;i 

289 

291 

193 

195 

145 

147 

115 

117 

95 

97 

83 

85 

71 

73 

11  (it 

1166 

291 

293 

193 

195 

145 

14T 

115 

117 

97 

99 

83 

85 

71 

73 

lliilj 

1168 

291 

293 

193 

195 

145 

147 

115 

117 

97 

99 

83 

85 

71 

73 

1168 

1170 

291 

293 

193 

195 

145 

147 

115 

117 

97 

99 

83 

85 

73 

75 

1170 

1172 

291 

293 

195 

197 

145 

147 

117 

119 

97 

99 

83 

85 

73 

75 

1172 

1171 

293 

295 

195 

197 

145 

147 

117 

119 

97 

99 

83 

•   85 

73 

75 

1174 

1176 

293 

295 

195 

197 

145 

147 

117 

119 

97 

99 

83 

85 

73 

75 

1176 

1178 

293 

295 

195 

197 

147 

149 

117 

119 

97 

99 

83 

85 

73 

75 

1178 

1180 

293 

295 

195 

197 

147 

149 

117 

119 

97 

99 

83 

85 

73 

75 

1180 

1182 

295 

297 

195 

197 

147 

149 

117 

119 

97 

99  . 

83 

85 

73 

75 

1182 

11M 

295 

297 

197 

199 

147 

149 

117 

119 

97 

99 

83 

85 

73 

75 

list 

1186 

295 

297 

197 

199 

117 

149 

117 

119 

97 

99 

83 

85 

73 

75 

rise, 

1188 

295 

297 

197 

199 

117 

149 

117 

119 

97 

99 

83 

H5 

73 

75 

1188 

1190 

297 

29!) 

197 

199 

147 

149 

117 

119 

99 

101 

83 

85 

73 

75 

1190 

lli»2 

297 

299 

197 

199 

147 

149 

119 

121 

99 

101 

85 

87 

73 

75 

1192 

11'.)  1 

297 

299 

197 

199 

149 

151 

119 

121 

99 

101 

85 

87 

73 

75 

1194 

11!)6 

297 

299 

199 

201 

149 

151 

119 

121 

99 

101 

85 

87 

73 

75 

1196 

1198 

29!l 

301 

199 

201 

149 

151 

119 

121 

99 

101 

85 

87 

73 

75 

1198 

1200 

299 

301 

191) 

201 

1  19 

151 

119 

121 

99 

101 

85 

87 

73 

75 

1200 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although  as  stated  in  text,  the  absdute  magnitude 
of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  SINGLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

CO 
IT 
D 

4 

POLES 

6 

POLES 

8 

POLES 

10 
POLES 

12 

POLES 

14 

POLES 

16 

POLES 

O 

3 

p 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

0 

d 

Z 

1202 

299 

301 

199 

201 

149 

151 

119 

121 

99 

101 

85 

87 

75 

77 

1202 

1204 

299 

301 

199 

201 

149 

151 

119 

121 

99 

101 

85 

87 

75 

77 

1204 

1206 

301 

303 

199 

201 

149 

151 

119 

121 

99 

101 

85 

~_$7 

75 

77 

12(>i; 

1208 

301 

303 

201 

203 

U9 

151 

119 

121 

99 

101 

85 

87 

75 

77 

1208 

1210 

301 

303 

201 

203 

151 

153 

119 

121 

99 

101 

85 

87 

75 

77 

1210 

1212 

301 

303 

201 

203 

151 

153 

121 

123 

99 

101 

85 

87 

75 

77 

1212 

1214 

803 

305 

201 

203 

151 

153 

121 

123 

101 

103 

85 

87 

75 

77 

1214 

1216 

303 

305 

201 

203 

151 

153 

121 

123 

101 

103 

85 

87 

75 

77 

1216 

1218 

303 

305 

201 

203 

151 

153 

121 

123 

101 

103 

85 

87 

75 

77 

1218 

1220 

303 

305 

203 

205 

151 

153 

121 

123 

101 

103 

87 

89 

75 

77 

1220 

1222 

305 

307 

203 

205 

151 

153 

121 

123 

101 

103 

87 

89 

75 

77 

1222 

1224 

305 

307 

203 

205 

151 

153 

121 

123 

101 

103 

87 

89 

75 

77 

1224 

1226 

305 

307 

203 

205 

153 

155 

121 

123 

101 

103 

87 

89 

75 

77 

1226 

1228 

305 

307 

2(13 

205 

153 

155 

121 

123 

J01 

103 

87 

89 

75 

77 

1228 

1230 

307 

309 

203 

205 

153 

155 

121 

123 

101 

103 

87 

89 

75 

77 

1230 

1232 

307 

309 

205 

207 

153 

155 

123 

125 

101 

103 

87 

89 

75 

77 

1232 

1234 

307 

309 

205 

207 

153 

155 

123 

125 

101 

103 

87 

89 

77 

79 

1234 

1236 

§07 

309 

205 

207 

153 

155 

123 

125 

101 

103 

87 

89 

77 

79 

1236 

1238 

309 

311 

205 

207 

153 

155 

123 

125 

103 

105 

87 

89 

77 

79 

1238 

1240 

309 

311 

205 

207 

153 

155 

123 

125 

103 

105 

87 

89 

77 

79 

1210 

1242 

309 

311 

205 

207 

155 

157 

123 

125 

103 

]  05 

87 

89 

77 

79 

1242 

1244 

309 

311 

207 

209 

155 

157 

123 

125 

103 

105 

87 

89 

77 

79 

1244 

1246 

311 

313 

207 

209 

155 

157 

123 

12.". 

103 

105 

87 

89 

77 

79 

1246 

1248 

311 

313 

207 

209 

155 

157 

123 

i'i:, 

103 

105 

89 

91 

77 

79 

1  24H 

1250 

311 

313 

207 

209 

155 

157 

123 

12.-, 

103 

105 

89 

91 

77 

79 

1250 

1252 

311 

313 

207 

209 

155 

157 

125 

127 

103 

105 

89 

91 

77 

79 

1252 

1254 

818 

315 

207 

209 

155 

157 

125 

127 

103 

105 

89 

91 

77 

79 

1254 

1256 

318 

315 

209 

211 

155 

157 

125 

127 

103 

105 

89 

91 

77 

79 

1256 

1258 

313 

315 

209 

211 

157 

159 

125 

127 

103 

105 

89 

91 

77 

79 

1258 

1260 

313 

315 

209 

211 

157 

159 

125 

127 

103 

105 

89 

91 

77 

79 

1260 

1262 

315 

317 

209 

211 

157 

159 

125 

127 

105 

107 

89 

91 

77 

79 

1262 

1264 

315 

317 

209 

211 

157 

159 

125 

127 

105 

107 

89 

91 

77 

79 

1264 

126G 

315 

317 

209 

211 

157 

159 

125 

127 

105 

107 

gg 

91 

79 

81 

1266 

1208 

815 

317 

211 

213 

157 

159 

125 

127 

105 

107 

89 

91 

79 

81 

1268 

1270 

317 

319 

211 

213 

157 

159 

125 

127 

105 

107 

89 

91 

79 

81 

1270 

1272 

317 

319 

211 

213 

157 

159 

127 

129 

105 

107 

89 

91 

79 

81 

1272 

1274 

317 

319 

211 

213 

159 

161 

127 

129 

105 

107 

89 

91 

79 

81 

1274 

127G 

317 

819 

211 

213 

159 

161 

127 

129 

105 

107 

91 

93 

79 

81 

1276 

1278 

319 

321 

211 

213 

15!) 

161 

127 

129 

105 

107 

91 

93 

79 

si 

1278 

1280 

319 

321 

213 

215 

159 

161 

127 

129 

105 

107 

91 

93 

79 

81 

I  -280 

1282 

319 

321 

213 

215 

159 

161 

127 

129 

105 

107 

91 

93 

79 

81 

1282 

1284 

319 

321 

213 

215 

159 

161 

127 

129 

105 

107 

91 

93 

79 

81 

128-1 

1286 

321 

323 

213 

215 

159 

161 

127 

129 

107 

109 

91 

93 

79 

81 

1286 

1288 

321 

323 

213 

215 

159 

161 

127 

129 

107 

109 

91 

93 

79 

81 

1288 

1290 

321 

323 

213 

215 

161 

163 

127 

129 

107 

109 

91 

93 

79 

81 

1290 

1292 

321 

323 

215 

217 

161 

163 

129 

131 

107 

109 

91 

93 

79 

81 

1292 

1294 

323 

325 

215 

217 

161 

163 

129 

131 

107 

109 

91 

93 

79 

81 

1294 

1296 

323 

325 

215 

217 

161 

163 

129 

131 

107 

109 

91 

93 

79 

SI 

1296 

1298 

323 

325 

215 

217 

161 

163 

129 

131 

107 

109 

91 

93 

SI 

83 

1298 

1300 

323 

325 

215 

217 

1(11 

163 

129 

131 

107 

109 

91 

93 

81 

83 

1300 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute  magnitude 
of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  SINGLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

No.  OF  CONDUCTORS 

4 

POLES 

6 

POLES 

8 

POLES 

10 
POLES 

12 

,  POLES 

14 

POLES 

16 

POLES 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

1302 

325 

327 

215 

217 

161 

163 

129 

131 

107 

109 

91 

93 

81 

83 

13(12 

1304 

325 

327 

217 

219 

161 

163 

129 

131 

107 

109 

93 

95 

81 

83 

1304 

i:;o6 

325 

327 

217 

219 

163 

165 

1  29 

131 

107 

109 

93 

95 

81 

83 

1306 

1308 

325 

327 

217 

219 

163 

165 

129 

131 

107 

109 

93 

95 

81 

83 

1308 

1310 

327 

329 

217 

219 

163 

165 

129 

131 

109 

111 

93 

95 

81 

83 

13.1.0 

1312 

327 

329 

217 

219 

163 

165 

131 

133 

109 

111 

98 

95 

81 

83 

1.312 

1314 

327 

329 

217 

219 

163 

]  65 

131 

133 

109 

11  1 

93 

95 

81 

83 

i:m 

1316 

327 

329 

219 

221 

163 

165 

131 

133 

109 

111 

93 

95 

81 

83 

1316 

1318 

329 

331 

219 

221 

163 

165 

131 

133 

109 

111 

93 

95 

81 

83 

1318 

1320 

329 

331 

219 

221 

163 

165 

131 

133 

109 

111 

93 

95 

81 

83 

1320 

1322 

329 

331 

219 

•2-21 

165 

167 

131 

133 

109 

111 

98 

95 

81 

83 

1322 

1324 

329 

331 

219 

221 

165 

167 

131 

133 

109 

111 

93 

95 

81 

83 

1324 

1326 

331 

333 

219 

221 

165 

167 

l:U 

133 

109 

111 

93 

55 

81 

83 

132(5 

1328 

331 

333 

221 

223 

165 

167 

131 

133 

109 

111 

93 

95 

81 

83 

132.8 

1330 

331 

333 

221 

22:! 

165 

167 

131 

133 

109 

111 

93 

95 

83 

85 

1330 

l  :;:•(•_' 

331 

883 

221 

223 

165 

167 

133 

135 

109 

111 

95 

97 

83 

85 

1332 

1334 

333 

335 

•2-2} 

223 

1  65 

167 

133 

135 

111 

U3 

95 

97 

83 

85 

1334 

1336 

333 

335 

221 

223 

165 

167 

133 

135 

111 

113 

95 

97 

83 

85 

1386 

1338 

333 

335 

221 

223 

167 

169 

133 

135 

111 

113 

95 

97 

83 

85 

1388 

1340 

333 

335 

223 

225 

167 

169 

133 

135 

111 

113 

95 

1)7 

83 

85 

1340 

1342 

335 

337 

223 

225 

167 

169 

133 

135 

111 

113 

95 

97 

83 

85 

1342 

13.fl 

335 

337 

223 

225 

167 

169 

133 

135 

111 

113 

95 

97 

83 

85 

1344 

1346 

335 

337 

223 

225 

167 

169 

133 

135 

111 

113 

96 

97 

83 

85 

1346 

13_48 

335 

337 

223 

225 

167 

169 

133 

135 

111 

113 

95 

97 

83 

85 

1348 

1350 

337 

339 

223 

225 

167 

169 

133 

135 

111 

113 

95 

97 

83 

85 

1350 

1352 

337 

339 

225 

227 

167 

169 

135 

137 

111 

113 

95 

97 

83 

85' 

1352 

1354 

337 

339 

225 

227 

169 

171 

135 

137 

111 

113 

95 

97 

88 

85 

1354 

K{5G 

337 

339 

225 

227 

169 

171 

135 

137 

111 

113 

95 

97 

83 

85 

1356 

1358 

339 

341 

'2  2r, 

227 

169 

171 

135 

137 

113 

115 

95 

97 

83 

85 

1358 

1360 

339 

341 

225 

227 

169 

171 

135 

137 

113 

115 

97 

99 

83 

85 

1360 

1362 

339 

341 

225 

227 

169 

171 

135 

137 

113 

115 

97 

99 

85 

87 

1362 

1364 

339 

341 

227 

229 

169 

171 

135 

137 

113 

115 

97 

99 

85 

87 

13(14 

1366 

341 

343 

227 

229 

169 

171 

135 

137 

113 

115 

97 

99 

85 

87 

1366 

1368 

341 

343 

227 

229 

169 

171 

135 

137 

1.13 

115 

97 

99 

85 

87 

1368 

1370 

341 

343 

227 

229 

171 

173 

135 

137 

113 

115 

97 

99 

85 

87 

1370 

1372 

341 

343 

227 

229 

171 

173 

137 

139 

113 

115 

97 

8S 

85 

87 

1372 

1374 

343 

345 

227 

229 

171 

173 

137 

139 

113 

115 

97 

99 

85 

87 

1374 

1376 

343 

345 

229 

231 

171 

173 

137 

139 

113 

115 

97 

99 

85 

87 

1376 

1378 

343 

345 

22!) 

231 

171 

173 

137 

139 

113 

115 

97 

99 

85 

87 

1378 

l.-sso 

343 

345 

22!) 

231 

.171 

173 

182 

139 

113 

115 

97 

99 

86 

87 

1380 

1382 

345 

347 

229 

231 

171 

17:! 

137 

139 

115 

117 

97 

99 

85 

87 

1382 

1384 

345 

3~47 

'2-2'.) 

231 

171 

173 

137 

139 

115 

117 

97 

99 

85 

87 

1384 

1386 

345 

347 

229 

231 

173 

175 

137 

139 

115 

117 

97 

99 

85 

87 

1380 

1388 

345 

347 

231 

233 

173 

175 

137 

139 

115 

117 

99 

101 

85 

87 

1388 

1390 

347 

349 

231 

233 

173 

175 

137 

139 

115 

117 

99 

101 

85 

87 

1390 

1392 

347 

349 

231 

233 

173 

175 

139 

141 

115 

117 

99 

101 

85 

87 

1392 

1.39.4 

347 

349 

231 

233 

173 

175 

139 

141 

115 

117 

99 

101 

87 

89 

1394 

1396 

347 

349 

231 

233 

173 

175 

139 

141 

115 

117 

99 

101 

87 

89 

1396 

1398 

349 

351 

231 

233 

173 

175 

139 

141 

115 

117 

99 

101 

87 

89 

1398 

1400 

849 

861 

233 

235 

173 

175 

139 

Ml 

115 

117 

99 

101 

87 

89 

1400 

Above  choice  of  P  tches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute  magnitude 
of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  SINGLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

CO 

c 
o 

4 
POLES 

6 

POLES 

8 

POLES 

10 

POLES 

12 
POLES 

14 
POLES 

16 

POLES 

No.OF  CONDUC" 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

1402 

349 

351 

233 

235 

175 

177 

139 

14] 

115 

117 

99 

101 

87 

89 

1402 

1104 

349 

351 

233 

235 

175 

177 

139 

141 

115 

117 

99 

101 

87 

89 

1404 

1400 

351 

353 

233 

235 

175 

177 

139 

141 

117 

119 

99 

101 

87 

89 

1406 

1408 

351 

353 

233 

235 

175 

177 

139 

141 

117 

119 

',)!) 

101 

87 

89 

1408 

1  lit) 

351 

353 

233 

235 

175 

177 

139 

141 

117 

119 

99 

101 

87 

89 

1410 

1  112 

351 

353 

235 

237 

175 

177 

141 

143 

117 

119 

99 

101 

87 

89 

1412 

1414 

353 

355 

235 

237 

175 

177 

141 

143 

117 

119 

99 

101 

87 

89 

1414 

1416 

353 

355 

235 

237 

175 

177 

141 

143 

117 

119 

101 

103 

87 

89 

1410 

i  us 

353 

355 

235 

237 

177 

179 

141 

143 

117 

119 

101 

103 

87 

89 

1418 

1420 

353 

_35_5 

235 

2:!7 

177 

179 

141 

143 

117 

119 

1.01 

103 

87 

89 

1420 

14-22 

355 

357 

235 

237 

177 

179 

141 

143 

117 

119 

101 

103 

87 

89 

1422 

1424 

355 

357 

237 

239 

177 

179 

141 

143 

117 

119 

101 

103 

87 

89 

1424 

1120 

355 

357 

237 

'239 

177 

179 

141 

143 

117 

119 

101 

103 

89 

91 

1420 

1428 

355 

357 

237 

239 

177 

179 

141 

143 

117 

119 

101 

103 

89 

91 

1428 

1430 

357 

359 

237 

239 

177 

179 

141 

143 

119 

121 

101 

103 

89 

91 

1430 

1432 

357 

359 

237 

239 

177 

179 

143 

145 

119 

121 

101 

103 

89 

91 

1432 

1434 

357 

359 

237 

239 

179 

181 

143 

145 

111) 

121 

101 

103 

89 

91 

1434 

1  130 

357 

359 

239 

241 

179 

181 

143 

145 

119 

121 

101 

103 

89 

91 

1436 

1438 

359 

861 

239 

241 

179 

181 

143 

145 

119 

121 

101 

103 

89 

91 

1438 

1440 

359 

361 

239 

241 

179 

181 

143 

145 

119 

121 

101 

103 

89 

91 

1440 

1442 

359 

301 

239 

241 

179 

181 

143 

145 

119 

121 

101 

103 

89 

91 

1442 

1444 

359 

301 

239 

241 

17'.) 

181 

143 

145 

119 

121 

103 

105 

89 

91 

1444 

1446 

301 

363 

239 

241 

179 

181 

143 

145 

119 

121 

103 

105 

89 

91 

1440 

1448 

301 

363 

241 

243 

179 

181 

143 

145 

119 

121 

103 

105 

89 

91 

1448 

1450 

301 

363 

241 

243 

181 

1  83 

143 

145 

11!) 

121 

103 

105 

89 

91 

1450 

!  152 

301 

363 

241 

243 

LSI 

183 

145 

147 

119 

121 

103 

105 

89 

91 

1452 

1454 

303 

365 

241 

243 

181 

183 

145 

147 

121 

123 

103 

105 

89 

91 

1454 

1450 

303 

365 

241 

243 

181 

183 

145 

147 

121 

123 

103 

105 

89 

91 

1450 

]  I'M 

363 

365 

241 

243 

181 

183 

145 

147 

121 

123 

103 

105 

91 

93 

1458 

1400 

363 

305 

243 

245 

181 

183 

145 

147 

121 

123 

103 

105 

91 

93 

1400 

1462 

365 

367 

243 

245 

181 

183 

145 

147 

121 

123 

103 

105 

91 

93 

1402 

HG4 

305 

307 

243 

245 

181 

183 

145 

147 

121 

123 

103 

105 

91 

93 

1404 

1460 

305 

307 

243 

245 

183 

185 

145 

147 

121 

123 

103 

105 

91 

93 

1466 

1408 

365 

367 

243 

245 

183 

185 

145 

147 

121 

123 

103 

105 

91 

93 

1468 

1470 

307 

369 

243 

245 

183 

185 

145 

147 

121 

123 

103 

105 

91 

93 

1470 

1472 

367 

ISO'.) 

245 

247 

183 

185 

147 

149 

121 

123 

105 

107 

91 

93 

1472 

1474 

367 

369 

245 

247 

183 

185 

147 

149 

121 

123 

105 

107 

91 

93 

1474 

1470 

367 

369 

245 

247 

183 

185 

147 

149 

121 

123 

105 

107 

91 

93 

1476 

1478 

369 

371 

245 

247 

183 

185 

147 

149 

123 

125 

105 

107 

91 

93 

1478 

1480 

369 

371 

245 

247 

183 

185 

147 

149 

123 

125 

105 

107 

91 

93 

1480 

1482 

309 

371 

245 

247 

185 

187 

147 

149 

123 

125 

105 

107 

1)1 

93 

1482 

1484 

369 

371 

247 

249 

185 

187 

147 

149 

123 

125 

105 

107 

91 

93 

1484 

1480 

371 

373 

247 

249 

185 

187 

147 

149 

123 

125 

105 

107 

91 

93 

1486 

1488 

371 

373 

247 

249 

1S5 

187 

147 

149 

123 

125 

105 

107 

1)1 

93 

1488 

Tl'.H) 

371 

373 

247 

249 

185 

187 

147 

149 

123 

125 

105 

107 

93 

96 

141)0 

14112 

371 

373 

247 

249 

185 

187 

149 

151 

123 

125 

105 

107 

93 

95 

14D2 

1494 

373 

375 

247 

249 

185 

187 

149 

151 

123 

125 

105 

107 

93 

95 

1494 

14110 

373 

375 

249 

251 

185 

187 

149 

151 

123 

125 

105 

107 

93 

95 

1496 

141(8 

373 

375 

249 

251 

187 

189 

149 

151 

123 

125 

105 

107 

93 

95 

1498 

1500 

373 

375 

249 

251 

187 

189 

149 

151 

123 

125 

107 

109 

93 

95 

1500 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute  magnitude 
of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  SINGLE  WINDINGS,  FOR  DRUM  ARMATURES. 

No.OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

No.OF  CONDUCTORS 

4 

POLES 

6 
POLES 

8 

POLES 

10 

POLES 

12 

POLES 

14 
POLES 

16 
POLES 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

1502 

375 

377 

249 

251 

187 

189 

119 

151 

125 

127 

107 

109 

93 

95 

1502 

1504 

375 

:;77 

21'.) 

251 

187 

189 

119 

151 

125 

127 

107 

109 

93 

95 

1501 

i:,u<; 

375 

:;77 

219 

251 

187 

1  si) 

149 

151 

125 

127 

1(17 

109 

93 

95 

1506 

150.8 

375 

:i77 

251 

253 

1X7 

18!) 

149 

151 

125 

127 

107 

109 

22 

95 

1508 

1510 

:;77 

379 

251 

253 

1M7 

189 

149 

151 

125 

127 

107 

109 

93 

95 

1510 

1  :,  I  2 

377 

:!7!) 

251 

25.5 

187 

1  89 

151 

153 

125 

127 

107 

109 

93 

95 

1512 

1511 

:!77 

:i7'.l 

251 

253 

1  Ml) 

191 

151 

153 

125 

127 

107 

109 

93 

95 

1511 

1510 

::77 

:!7lt 

251 

25:; 

]  SI) 

191 

151 

153 

125 

127 

11(7 

109 

93 

95 

1510 

1518 

:!7D 

381 

25  1 

253 

1.H9 

191 

151 

153 

125 

127 

107 

109 

93 

95 

1518 

1520 

379 

38| 

253 

255 

189 

191 

151 

153 

125 

127 

1(17 

109 

93 

95 

1520 

1522 

379 

381 

253 

255 

189 

191 

151 

153 

125 

127 

107 

109 

95 

97 

1522 

1521 

:!7'.» 

38i 

25:', 

255 

189 

191 

151 

153 

125 

127 

1(17 

109 

95 

97 

1  52  1 

152<J 

381 

:is:i 

253 

255 

18'.) 

191 

151 

153 

127 

129 

Hi7 

109 

95 

97 

1520 

1528 

3.81 

383 

253 

255 

189 

191 

151 

153 

127 

12!) 

109 

111 

95 

97 

1528 

15:!l) 

381 

383 

2.-,.; 

255 

191 

193 

151 

153 

127 

129 

109 

111 

95 

97 

1530 

ir,:!2 

:;si 

383 

255 

257 

191 

I1.):: 

153 

155 

127 

129 

109 

111 

95 

97 

1532 

i.v;i 

383 

385 

255 

257 

191 

193 

153 

155 

127 

129 

109 

111 

95 

97 

1531 

1530 

383 

385 

255 

257 

191 

1!):', 

153 

155 

127 

129 

1(1!) 

111 

95 

97 

1530 

153,8 

:;s:; 

385 

255 

257 

191 

193 

153 

155 

127 

129 

109 

111 

95 

97 

1  538 

1.-,  Ill 

383 

:;s5 

255 

257 

19] 

1!):; 

153 

1  55 

127 

12!) 

109 

111 

95 

97 

1510 

15(2 

;$S5 

;i87 

255 

257 

19! 

193 

15:', 

1  55 

127 

1  29 

109 

111 

95 

97 

1512 

1511 

385 

;-',H7 

257 

259 

191 

193 

153 

1  55 

127 

129 

109 

111 

95 

97 

1544 

1510 

385 

:;s7 

257 

259 

193 

195 

153 

1  55 

127 

129 

109 

111 

95 

97 

1  510 

15-  IS 

:;sr, 

387 

257 

259 

193 

195 

153 

155 

127 

129 

109 

111 

95 

97 

1518 

1550 

1(87 

389 

257 

25!) 

193 

195 

153 

1  55 

129 

131 

109 

111 

95 

97 

1550 

1552 

387 

389 

257 

259 

193 

195 

!  55 

157 

129 

131 

109 

111 

95 

97 

1552 

1  55  1 

387 

389 

257 

259 

193 

195 

155 

157 

129 

131 

109 

111 

97 

99 

1  55  1 

1550 

387 

389 

259 

261 

193 

195 

155 

157 

129 

131 

111 

113 

97 

99 

1556 

1  558 

389 

391 

2.  V.I 

261 

193 

195 

155 

157 

129 

131 

111 

113 

97 

99 

1  558 

15(10 

389 

31)1 

259 

261 

193 

195 

155 

157 

129 

131 

111 

113 

97 

99 

1500 

1502 

389 

31)1 

259 

261 

195 

197 

155 

157 

129 

131 

111 

113 

97 

99 

1502 

1501 

389 

391 

259 

201 

1  1)5 

197 

155 

157 

129 

131 

111 

113 

97 

99 

1564 

1566 

391 

393 

251) 

201 

195 

197 

1  55 

157 

129 

131 

111 

113 

97 

99 

1500 

1508 

391 

393 

201 

203 

195 

197 

1  55 

157 

129 

131 

111 

113 

97 

99 

1508 

1570 

391 

393 

201 

203 

1  1)5 

197 

155 

157 

1  29 

131 

111 

113 

97 

99 

1  570 

1572 

;ii)l 

393 

261 

20:', 

11)5 

197 

157 

159 

129 

131 

111 

113 

97 

99 

1572 

1571 

393 

395 

261 

203 

195 

197 

157 

1  59 

131 

133 

111 

113 

97 

99 

1571 

l.-)7(J 

393 

395 

201 

203 

195 

197 

157 

1  51) 

131 

133 

111 

113 

97 

99 

1570 

1578 

393 

395 

201 

263 

197 

199 

157 

151) 

131 

133 

111 

113 

97 

99 

1578 

I5SO 

:•,:):; 

31)5 

203 

265 

11)7 

199 

157 

1  59 

131 

133 

111 

113 

97 

99 

1580 

158-j 

395 

31)7 

203 

205 

197 

199 

1  57 

159 

131 

133 

111 

113 

97 

99 

1582 

1584 

395 

397 

203 

205 

197 

199 

157 

159 

131 

133 

113 

115 

97 

99 

1581 

1586 

395 

397 

203 

265 

197 

199 

157 

159 

131 

133 

113 

115 

99 

101 

1586 

1588 

395 

31)7 

203 

205 

197 

199 

157 

159 

131 

133 

113 

115 

99 

101 

1  588 

1590 

397 

399 

203 

20,5 

197 

199 

157 

159 

131 

133 

113 

115 

99 

101 

1590 

151)2 

397 

399 

265 

2C.7 

197 

19!) 

159 

161 

131 

133 

113 

115 

99 

101 

1592 

J51I1 

:t-.)7 

399 

205 

207 

199 

2:11 

159 

101 

131 

133 

113 

115 

99 

101 

1591 

151)0 

:i-.)7 

399 

205 

207 

199 

201 

159 

161 

131 

133 

113 

115 

99 

101 

15110 

1598 

399 

401 

205 

207 

199 

201 

159 

161 

133 

135 

113 

115 

1)9 

nil 

1598 

1000 

399 

401 

205 

207 

199 

201 

159 

161 

133 

135 

113 

115 

99 

101 

1600 

Above  choice  of  P  tohes  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute  magnitude 
of  average  pitch  may  be  varied  within  reasonable  limits 

WINDING  TABLES   FOR   MULTIPLE-CIRCUIT,   DOUBLE   WINDINGS 

FOR  DRUM   ARMATURES. 


MULTIPLE-CIRCUIT,  DOUBLE  WINDINGS,  FOR  DRUM  ARMATURES. 

R  E-  EN  T  RANGY 

No.OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

No.  OF  CONDUCTORS 

4 

POLES 

6 

POLES 

8 
POLES 

10 

POLES 

12 

POLES 

14 
POLES 

16 

POLES 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

-B 

GD 

202 

49 

53 

31 

35 

23 

27 

19 

23 

15 

19 

13 

17 

11 

15 

202 

00 

204 

49 

53 

31 

86 

23 

27 

19 

23 

15 

19 

13 

17 

11 

15 

204 

SB 

206 

49 

53 

33 

ri!7 

23 

27 

19 

23 

15 

11) 

13 

17 

11 

15 

206 

oo 

208 

49 

53 

33 

37 

23 

27 

19 

23 

15 

19 

13 

17 

11 

15 

208 

GD 

210 

51 

55 

33 

37 

25 

29 

19 

23 

15 

19 

13 

17 

11 

15 

210 

oo 

212 

51 

55 

33 

37 

25 

29 

19 

23 

15 

19 

13 

17 

11 

15 

212 

GD 

214 

51 

55 

33 

87 

25 

29 

19 

23 

15 

19 

13 

17 

11 

15 

214 

00 

216 

51 

55 

33 

37 

25 

29 

19 

23 

15 

19 

13 

17 

11 

15 

216 

GD 

218 

53 

57 

35 

39 

25 

29 

19 

23 

17 

21 

13 

17 

11 

15 

218 

oo 

220  . 

53 

57 

35 

39 

25 

29 

19 

23 

17 

21 

13 

17 

11 

15 

220 

_Cfi3 

222 

53 

57 

35 

39 

25 

29 

21 

25 

17 

21 

13 

17 

11 

15 

222 

00 

224 

53 

57 

35 

39 

25 

29 

21 

25 

17 

21 

13 

17 

11 

15 

224 

GD 

226 

55 

59 

35 

39 

27 

31 

21 

25 

17 

21 

15 

19 

13 

17 

226 

oo 

228 

55 

59 

35 

39 

27 

31 

21 

25 

17 

21 

15 

19 

13 

17 

228 

GD 

230 

55 

59 

37 

41 

27 

31 

21 

25 

17 

21 

15 

19 

13 

17 

230 

00 

232 

55 

59 

37 

41 

27 

31 

21 

25 

17 

21 

15 

19 

13 

17 

232 

GD 

234 

57 

61 

37 

41 

27 

31 

21 

25 

17 

21 

15 

19 

13 

17 

234 

00 

236 

57 

61 

37 

41 

27 

31 

21 

25 

17 

21 

15 

19 

13 

17 

236 

go 

238 

57 

61 

37 

41 

27 

31 

21 

25 

17 

21 

15 

19 

13 

17 

238 

oo 

240 

57 

61 

37 

41 

;  27 

31 

21 

25 

17 

21 

15 

19 

13 

17 

240 

GD 

242 

59 

63 

39 

43 

29 

33 

23 

27 

19 

23 

15 

19 

13 

17 

242 

00 

244 

59 

58 

39 

43 

29 

33 

23 

27 

19 

23 

15 

19 

13 

17 

244 

(53 

246 

59 

63 

39 

43 

29 

33 

23 

27 

19 

23 

15 

19 

13 

17 

246 

oo 

248 

59 

63 

39 

£3 

29 

33 

23 

27 

19 

23 

15 

19 

13 

17 

248 

(33 

250 

61 

65 

39 

43 

29 

33 

23 

27 

19 

23 

15 

19 

13 

17 

250 

00 

252 

61 

65 

39 

43 

29 

33 

23 

27 

11) 

23 

15 

19 

13 

17 

252 

(S3 

254 

61 

65 

41 

45 

29 

33 

23 

27 

19 

23 

17 

21 

13 

17 

254 

00 

256 

61 

65 

41 

45 

29 

33 

23 

27 

19 

23 

17 

21 

13 

17 

256 

go 

258 

63 

67 

41 

45 

31 

35 

23 

27 

19 

23 

17 

21 

15 

19 

258 

00 

260 

63 

67 

41 

45 

31 

35 

23 

27 

19 

23 

17 

21 

15 

19 

260 

GD 

262 

63 

67 

41 

-15 

31 

35 

25 

29 

19 

23 

17 

21 

15 

19 

262 

oo 

264 

63 

67 

41 

45 

31 

35 

25 

29 

19 

23 

17 

21 

15 

19 

264 

(53 

266 

65 

69 

43 

47 

31 

35 

25 

29 

21 

25 

17 

21 

15 

19 

266 

oo 

268 

65 

69 

43 

47 

31 

35 

25 

29 

21 

25 

17 

21 

15 

19 

268 

GO 

270 

65 

69 

43 

47 

31 

35 

25 

2!) 

21 

25 

17 

21 

15 

19 

270 

00 

272 

65 

69 

43 

47 

31 

35 

25 

29 

21 

25 

17 

21 

15 

19 

272 

C53 

274 

67 

71 

IS 

47 

33 

37 

25 

29 

21 

25 

17 

21 

J6 

19 

274 

00 

276 

67 

71 

43 

47 

33 

37 

25 

29 

21 

25 

17 

21 

15 

19 

276 

GD 

278 

67 

71 

45 

49 

33 

37 

25 

29 

21 

25 

17 

21 

15 

19 

278 

oo 

280 

67 

71 

45 

49 

33 

37 

25 

29 

21 

25 

17 

21 

15 

19 

280 

GD 

282 

69 

7:', 

45 

49 

33 

37 

27 

31 

21 

25 

19 

23 

15 

19 

282 

oo 

m 

69 

73 

,45 

49 

33 

37 

27 

31 

21 

25 

19 

23 

15 

19 

284 

GD 

286 

69 

73 

45 

49 

33 

37 

27 

31 

21 

25 

19 

23 

15 

19 

286 

oo 

288 

69 

73 

45 

49 

33 

37 

27 

31 

21 

25 

19 

23 

15 

19 

288 

GD 

290 

71 

75 

47 

51 

35 

39 

27 

31 

23 

27 

19 

23 

17 

21 

290 

oo 

292 

71 

75 

47 

51 

35 

39 

27 

31 

23 

27 

19 

23 

17 

21 

292 

GD 

294 

71 

75 

47 

51 

35 

39 

27 

31 

23 

27 

19 

23 

17 

21 

294 

oo 

2% 

71 

75 

47 

51 

35 

39 

27 

31 

23 

27 

19 

23 

17 

21 

296 

GD 

208 

73 

77 

47 

51 

35 

39 

27 

31 

23 

27 

19 

23 

17 

21 

298 

00 

300 

73 

77 

47 

51 

35 

39 

27 

31 

23 

27 

B 

23 

17 

21 

;',oo 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute 
magnitude  of  average  pitch  may  be  varied  within  reasonable  Omits. 

MULTIPLE-CIRCUIT,  DOUBLE  WINDING,  FOR  DRUM  ARMATURES. 

RE-EN  TRANCY 

No.OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

en 
• 
0 

4 

POLES 

6 

POLES 

8 

POLES 

10 

POLES 

12 

POLES 

14 

POLES 

16 

POLES 

CONDUC1 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

O 

d 

Z 

GD 

302 

73 

77 

49 

53 

35 

39 

29 

33 

23 

27 

19 

23 

17 

21 

302 

00 

304 

73 

77 

49 

53 

35 

39 

29 

33 

23 

27 

19 

23 

17 

21 

304 

C2> 

3()G 

75 

79 

49 

53 

37 

41 

29 

33 

23 

27 

19 

23 

17 

21 

306 

oo 

308 

75 

79 

49 

53 

37 

41 

29 

33 

23 

27 

19 

23 

17 

21 

308 

GZ> 

310 

75 

79 

49 

53 

37 

41 

29 

33 

23 

27 

21 

25 

17 

21 

310 

oo 

312 

75 

79 

49 

53 

37 

41 

29 

33 

23 

27 

21 

25 

17 

21 

312 

GD 

314 

77 

81 

51 

55 

37 

41 

29 

33 

25 

29 

21 

25 

17 

21 

314 

00 

316 

77 

81 

51 

55 

37 

41 

29 

33 

25 

29 

21 

25 

17 

21 

316 

GD 

318 

77 

81  " 

51 

55 

37 

41 

29 

33 

25 

29 

21 

25 

J7 

21 

318 

oo 

320 

77 

81 

51 

55 

37 

41 

29 

33 

25 

29 

21 

h    25 

17 

21 

320 

GD 

322 

79 

83 

51 

55 

39 

43 

31 

35 

25 

29 

21 

25 

19 

23 

322 

oo 

324 

79 

83 

51 

55 

39 

43 

31 

35 

25 

2§ 

21 

25 

19 

23 

324 

GD 

320 

79 

83 

53 

57 

39 

43 

31 

35 

25 

29 

21 

25 

19 

23 

326 

oo 

328 

79 

83 

53 

57 

39 

43 

31 

35 

25 

29 

21 

25 

19 

23 

328 

GD 

330 

81 

85 

53 

57 

39 

43 

31 

35 

25 

29 

21 

25 

19 

23 

330 
332 

oo 

332 

81 

85 

53 

57 

39 

43 

31 

35 

25 

29 

21 

25 

19 

23 

GD 

334 

81 

85 

53 

57 

39 

43 

31 

35 

25 

29 

21 

25 

19 

23 

33i 

oo 

336 

81 

85 

53 

57 

39 

43 

31 

35 

25 

29 

21 

25 

19 

23 

336 

GD 

338 

83 

87 

55 

59 

41 

-15 

31 

35 

27 

31 

23 

27 

19 

23 

338 

00 

340 

83 

87 

55 

59 

41 

45 

31 

35 

27 

31 

23 

27 

19 

23 

340 

go 

342 

83 

87 

55 

59 

41 

45 

33 

37 

27 

31 

23 

27 

19 

23 

342 

00 

344 

83 

87 

55 

59 

41 

45 

33 

37 

27 

31 

23 

27 

19 

23 

344 

GD 

310 

85 

89 

55 

59 

41 

45 

33 

37 

27 

31 

23 

27 

19 

23 

13-16 

oo 

348 

85 

89 

55 

59 

41 

45 

33 

37 

27 

31 

23 

27 

19 

23 

348 

GD 

350 

85 

89 

5T 

61 

41 

45 

33 

37 

27 

31 

23 

27 

19 

23 

350 

oo 

352 

85 

89 

57 

61 

41 

45 

33 

37 

27 

31 

23 

27 

19 

23 

352 

GD 

354 

87 

91 

57 

61 

43 

47 

33 

37 

27 

31 

23 

27 

21 

25 

351 

oo 

350 

87 

91 

57 

61 

43 

47 

33 

37 

27 

31 

23 

27 

21 

25 

356 

GD 

358 

87 

91 

57 

"  ol 

43 

47 

33 

37 

27 

31 

23 

27 

21 

25 

358 

oo 

360 

87 

91 

57 

61 

43 

47 

33 

37 

27 

31 

r~23 

27 

21 

25 

3<;o 

GD 

362 

89 

93 

59 

63 

43 

47 

35 

39 

29 

33 

23 

27 

21 

25 

362 

00 

364 

89 

93 

59 

63 

43 

47 

35 

39 

29 

33 

23 

27 

21 

25 

304 

GD 

300 

89 

93 

59 

63 

43 

47 

35 

39 

29 

33 

25 

29 

21 

25 

366 

oo 

§38 

89 

93 

59 

63 

43 

47 

35 

39 

29 

33 

25 

29 

21 

25 

368 

GD 

370 

91 

95 

59 

63 

45 

49 

35 

39 

29 

33 

25 

29 

21 

25 

370 

oo 

372 

91 

95 

59 

63 

45 

49 

35 

39 

29 

33 

25 

29 

21 

25 

372 

O 

374 

91 

95 

61 

65 

45 

49 

35 

39 

29 

33 

25 

29 

21 

25 

374 

00 

376 

91 

95 

61 

65 

45 

-1!) 

35 

39 

29 

33 

25 

29 

21 

25 

370 

GD 

378 

93 

97 

61 

65 

45 

49 

35 

39 

29 

33 

25 

29 

21 

25 

378 

00 

380 

93 

97 

61 

65 

45 

49 

35 

39 

29 

33 

25 

29 

21 

25 

3Sli 

GD 

382 

93 

97 

61 

65 

45 

49 

37 

41 

29 

33 

25 

29 

21 

25 

382 

oo 

384 

93 

97 

61 

65 

45 

49 

37 

41 

29 

33 

25 

29 

21 

25 

381 

(2) 

386 

95 

99 

63 

67 

47 

51 

37 

41 

31 

35 

25 

29 

23 

27 

386 

oo 

388 

95 

99 

63 

67 

47 

51 

37 

41 

31 

35 

25 

29 

23 

27 

388 

GD 

390 

95 

99 

58 

67 

47 

51 

37 

41 

31 

35 

25 

29 

23 

27 

390 

oo 

392 

95 

99 

63 

67 

47 

51 

37 

41 

31 

35 

25 

29 

23 

27 

392 

GD 

394 

97' 

fioi- 

63 

67 

47 

51 

37 

41 

31 

35 

27 

31 

23 

27 

394 

oo 

396 

97 

ng 

63 

67 

47 

51 

37 

41 

31 

35 

27 

31 

23 

27 

396 

CS) 

398 

97 

101 

65 

69 

47 

51 

37 

41 

31 

35 

27 

31 

23 

27 

398 

oo 

-KKI 

97 

101 

G5 

69 

47 

51 

37 

41 

31 

35 

27 

31 

23 

27 

400 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute 
magnitude  of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  DOUBLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-ENTRANCY 

No.OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

No.  OF  CONDUCTORS 

4 

POLES 

6 

POLES 

8 

POLES 

10 

POLES 

12 

POLES 

14 

POLES 

16 

POLES 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

CD 

402 

99 

103 

65 

69 

49 

53 

39 

43 

31 

35 

27 

31 

23 

27 

402 

00 

404 

'.)'.) 

103 

65 

69 

49 

53 

39 

43- 

31 

35 

27 

31 

23 

27 

404 

CD 

406 

99 

103 

65 

69 

49 

53 

39 

43 

31 

35 

•27 

31 

23 

27 

406 

00 

408 

99 

103 

65 

69 

49 

53 

39 

43 

31 

35 

27 

31 

23 

27 

408 

£22 

410 

101 

105 

67 

71 

49 

53 

39 

43 

88 

37 

27 

31 

23 

27 

410 

oo 

412 

101 

105 

67 

71 

49 

53 

39 

43 

33 

37 

27 

31 

23 

27 

412 

CD 

414 

101 

105 

67 

71 

49 

53 

39 

43 

33 

37 

27 

31 

23 

27 

414 

00 

416 

101 

105 

67 

71 

49 

68 

39 

43 

33 

37 

27 

31 

23 

27 

416 

go 

418 

103 

107 

67 

71 

51 

55 

39 

43 

33 

37 

27 

31 

25 

29 

418 

00 

420 

103 

107 

67 

71 

51 

55 

39 

43 

33 

37 

27 

31 

25 

29 

420 

CD 

422 

103 

107 

69 

73 

51 

55 

41 

45 

33 

37 

29 

33 

25 

29 

422 

oo 

424 

103 

107 

69 

73 

51 

55 

41 

45 

33 

37 

29 

33 

25 

29 

424 

CD 

426 

105 

109 

69 

73 

51 

55 

41 

45 

33 

37 

22 

33 

25 

29 

426 

oo 

428 

105 

109 

69 

73 

51 

55 

41 

45 

33 

37 

29 

33 

25 

29 

428 

CD 

430 

105 

109 

69 

73 

51 

55 

41 

45 

33 

37 

29 

33 

25 

29 

430 

00 

432 

105 

109 

69 

73 

51 

55 

41 

45 

33 

37 

29 

33 

25 

29 

432 

CD 

434 

107 

111 

71 

75 

53 

57 

41 

45 

35 

39 

29 

33 

25 

29 

434 

oo 

436 

107 

111 

71 

75 

53 

57 

41 

45 

35 

39 

29 

33 

25 

29 

436 

CD 

438 

107 

111 

71 

75 

53 

57 

41 

45 

35 

39 

29 

33 

25 

29 

438 

00 

440 

107 

111 

71 

75 

53 

57 

41 

45 

35 

39 

29 

33 

25 

29 

440 

CD 

442 

109 

113 

71 

75 

53 

57 

43 

47 

35 

39 

29 

33 

25 

29 

442 

00 

444 

109 

113 

71 

75 

53 

57 

43 

47 

35 

39 

29 

33 

25 

29 

444 

CD 

446 

10'.) 

113 

73 

77 

53 

57 

43 

47 

35 

39 

29 

33 

25 

29 

446 

oo 

448 

109 

113 

73 

77 

53 

57 

43 

47 

35 

39 

29 

33 

25 

29 

448 

oa 

450 

111 

115 

73 

77 

55 

59 

43 

47 

35 

39 

31 

35 

27 

31 

450 

oo 

452 

111 

115 

73 

77 

55 

59 

43 

47 

35 

39 

31 

35 

27 

31 

452 

CD 

454 

111 

115 

73 

77 

55 

59 

43 

47 

35 

39 

31 

35 

27 

31 

454 

00 

J456 

111 

115 

73 

77 

55 

59 

43 

47 

35 

39 

31 

35 

27 

31 

456 

02 

458 

113 

117 

75 

79 

55 

69 

43 

47 

37 

41 

31 

35 

27 

31 

458 

00 

460 

113 

117 

75 

79 

55 

59 

43 

47 

37 

41 

31 

35 

27 

31 

460 

CD 

462 

113 

117 

75 

79 

55 

59 

45 

49 

37 

41 

31 

35 

27 

31 

462 

oo 

464 

113 

117 

75 

79 

55 

59 

45 

49 

37 

41 

31 

35 

27 

31 

464 

CD 

466 

115 

119 

75 

79 

57 

61 

45 

49 

37 

41 

31 

35 

27 

31 

460 

oo 

468 

115 

119 

75 

79 

57 

61 

45 

49 

37 

41 

31 

35 

27 

31 

468 

CD 

470 

115 

119 

77 

81 

57 

61 

45 

49 

37 

41 

31 

35 

27 

31 

470 

oo 

472 

115 

119 

77 

81 

57 

61 

45 

49 

37 

41 

31 

35 

27 

31 

472 

CD 

474 

117 

121 

77 

81 

57 

61 

45 

49 

37 

41 

31 

86 

27 

31 

474 

oo 

476 

117 

121 

77 

81 

57 

61 

45 

49 

37 

41 

31 

35 

27 

31 

476 

CD 

478 

117 

121 

77 

81 

57 

61 

45 

49 

37 

41 

33 

37 

27 

31 

478 

00 

480 

117 

121 

77 

81 

57 

61 

45 

49 

37 

41 

33 

37 

27 

31 

480 

CD 

482 

119 

123 

79 

83 

59 

63 

47 

51 

39 

43 

33 

37 

29 

33 

482 

00 

484 

119 

123 

79 

83 

59 

63 

47 

51 

39 

43 

33 

37 

29 

33 

484 

CD 

486 

119 

123 

79 

83 

59 

63 

47 

51 

39 

43 

88 

37 

29 

33 

486 

oo 

488 

119 

123 

79 

83 

59 

63 

47 

51 

39 

43 

88 

37 

29 

33 

488 

CD 

490 

121 

125 

79 

83 

59 

63 

47 

51 

89 

43 

33 

37 

29 

33 

490 

00 

492 

121 

125 

79 

83 

59 

63 

47 

51 

39 

43 

33 

37 

29 

33 

492 

CD 

494 

121 

125 

81 

85 

59 

63 

47 

51 

39 

43 

33 

37 

29 

33 

494 

oo 

4% 

121 

125 

81 

85 

59 

63 

47 

51 

39 

43 

BJ 

37 

29 

33 

496 

CD 

498 

123 

127 

81 

85 

61 

65 

47 

51 

39 

43 

33 

37 

29 

33 

498 

oo 

500 

123 

127 

81 

85 

61 

65 

47 

51 

39 

43 

33 

37 

29 

33 

500 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute 
magnitude  of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  DOUBLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-ENTRANCY 

No.OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

CO 

• 
O 

4 
POLES 

6 

POLES 

8 

POLES 

10 
POLES 

12 

POLES 

14 

POLES 

16 

POLES 

CONDUCT 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

o 

o 

Z 

CE) 

502 

123 

127 

81 

85 

61 

65 

49 

53 

39 

43 

33 

37 

29 

33 

502 

00 

504 

123 

127 

81 

85 

61 

65 

49 

53 

39 

43 

33 

37 

29 

33 

504 

SO 

506 

125 

129 

83 

87 

61 

65 

49 

53 

41 

45 

35 

39 

29 

33 

506 

oo 

508 

125 

121) 

815 

87 

61 

65 

49 

53 

41 

45 

35 

39 

29 

33 

5  OS 

CE> 

510 

125 

129 

83 

87 

61 

65 

49 

53 

41 

45 

35 

39 

29 

33 

510 

oo 

512 

125 

129 

83 

87 

61 

65 

49 

53 

41 

45 

35 

39 

29 

33 

512 

CE> 

514 

127 

131 

83 

87 

63 

67 

49 

53 

41 

45 

35 

39 

31 

35 

514 

oo 

516 

127 

131 

83 

87 

63 

67 

49 

BJ 

41 

45 

35 

31)  __ 

31 

35 

516 

CE> 

518 

127 

131 

85 

89 

63 

67 

49 

53 

41 

45 

35 

39 

31 

35 

518 

oo 

520 

127 

131 

85 

89 

63 

67 

49 

53 

41 

45 

35 

aa_ 

31 

35 

520 

(5) 

522 

129 

133 

85 

89 

63 

67 

51 

55 

41 

45 

35 

39 

31 

35 

522 

00 

524 

129 

133 

85 

89 

63 

67 

51 

55 

41 

45 

35 

39 

31 

85 

r.;i  i 

CE> 

526 

129 

133 

85 

89 

63 

67 

51 

55 

41 

•45 

35 

39 

31 

35 

526 

oo 

528 

129 

133 

85 

89 

63 

67 

51 

55 

41 

45 

35 

39 

31 

35 

528 

O 

530 

131 

135 

87 

91 

65 

69 

51 

55 

43 

47 

35 

39 

31 

35 

530 

00 

532 

131 

135 

87 

91 

65 

69 

51 

55 

43 

47 

35 

39 

31 

35 

532 

CE> 

534 

131 

135 

87 

91 

65 

69 

51 

55 

43 

47 

37 

41 

31 

35 

534 

oo 

536 

131 

135 

87 

91 

65 

69 

51 

55 

43 

47 

37 

41 

31 

35 

536 

CE> 

538 

133 

137 

87 

91 

65 

69 

51 

55 

43 

47 

37 

41 

31 

35 

538 

00 

540 

133 

137 

87 

91 

65 

69 

51 

55 

43 

47 

37 

41 

31 

35 

540 

CD 

542 

133 

137 

89 

93 

65 

69 

53 

57 

43 

47 

37 

41 

31 

35 

542 

oo 

544 

133 

137 

89 

93 

65 

69 

53 

57 

43 

47 

37 

41 

31 

35 

544 

CE> 

546 

135 

139 

89 

93 

67 

71 

53 

57 

43 

47 

37 

41 

33 

37 

546 

00 

548 

135 

139 

89 

93 

67 

71 

53 

57 

43 

47 

37 

41 

33 

37 

548 

CE> 

550 

135 

139 

89 

93 

67 

71 

53 

57 

43 

47 

37 

41 

33 

37 

550 

00 

552 

135 

139 

89 

93 

67 

71 

53 

57 

43 

47 

37 

41 

33 

37 

552 

CE) 

554 

137 

141 

91 

95 

67 

71 

53 

57 

45 

49 

37 

41 

33 

37 

554 

00 

556 

137 

141 

91 

95 

(',7 

71 

53 

57 

45 

49 

37 

41 

33 

37 

556 

CE) 

558 

137 

141 

91 

95 

67 

71 

53 

57 

45 

49 

37 

41 

33 

37 

558 

oo 

560 

137 

141 

91 

95 

67 

71 

53 

57 

45 

49 

37 

41 

33 

37 

560 

CE) 

562 

139 

143 

91 

95 

69 

73 

55 

59 

45 

49 

39 

43 

33 

37 

662 

00 

564 

139 

143 

91 

95 

69 

73 

55 

59 

45 

49 

39 

43 

33 

37 

504 

CE) 

566 

139 

143 

93 

97 

69 

73 

55 

59 

45 

49 

39 

43 

33 

37 

566 

oo 

568 

139 

143 

93 

97 

69 

73 

55 

59 

45 

49 

39 

43 

33 

37 

508 

CE) 

570 

141 

145 

93 

97 

69 

73 

55 

59 

45 

49 

39 

43 

33 

37 

570 

00 

572 

141 

145 

93 

97 

69 

73 

55 

59 

45 

49 

39 

43 

33 

37 

572 

CE) 

574 

141 

145 

93 

97 

69 

73 

55 

59 

45 

49 

39 

43 

83 

37 

574 

oo 

576 

141 

145 

93 

97 

69 

73 

55 

59 

45 

49 

39 

43 

33 

37 

570 

CE) 

578 

143 

147 

95 

99 

71 

75 

55 

59 

47 

51 

39 

43 

35 

39 

578 

oo 

580 

143 

147 

95 

99 

71 

75 

55 

59 

47 

51 

39 

43 

35 

39 

580 

CE) 

582 

143 

147 

95 

99 

71 

75 

57 

61 

47 

51 

39 

43 

35 

39 

582 

00 

584 

143 

147 

95 

99 

71 

75 

57 

61 

47 

51 

39 

43 

35 

89 

584 

CE) 

580 

145 

149 

95 

99 

71 

75 

57 

61 

47 

51 

39 

43 

35 

39 

586 

00 

588 

1  15 

149 

95 

99 

71 

75 

57 

61 

47 

51 

39 

43 

35 

39 

588 

CE> 

5  'JO 

145 

149 

97 

101 

71 

75 

57 

61 

47 

51 

41 

45 

35 

39 

590 

00 

592 

145 

149 

97 

101 

71 

75 

57 

61 

47 

51 

41 

45 

35 

39 

592 

CE) 

594 

147 

151 

97 

101 

73 

77 

57 

61 

47 

51 

41 

45 

35 

31) 

51)4 

oo 

596 

147 

151 

97 

101 

73 

77 

57 

61 

47 

51 

41 

45 

35 

39 

596 

CE> 

51)8 

147 

151 

97 

101 

73 

77 

57 

61 

47 

51 

41 

45 

35 

39 

598 

oo 

000 

147 

151 

97 

1U1 

73 

77 

57 

61 

47 

51 

41 

45 

35 

39 

600 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute 
magnitude  of  average  pitch  ma'y  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  DOUBLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-ENTRANCY 

No.OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

No.OF  CONDUCTORS 

4 

POLES 

6 

POLES 

8 
POLES 

10 

POLES 

12 
POLES 

14 

POLES 

16 

POLES 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

GD 

r,02 

149 

153 

99 

103 

73 

77 

59 

63 

49 

53 

41 

45 

35 

39 

602 

oo 

604 

149 

153 

99 

103 

73 

77 

59 

63 

49 

53 

41 

45 

35 

39 

604 

GD 

606 

149 

153 

99 

103 

73 

77 

55 

63 

49 

53 

41 

45 

35 

39 

606 

oo 

608 

149 

153 

9SJ 

103 

73 

77 

59 

63 

49 

53 

41 

45 

35 

39 

608 

GD 

610 

151 

155 

99 

103 

75 

79 

59 

63 

49 

53 

41 

45 

37 

41 

610 

oo 

612 

151 

155 

99 

103 

75 

79 

59 

68 

49 

53 

41 

45 

37 

41 

612 

GO 

614 

151 

155 

101 

105 

75 

79 

59 

63 

49 

53 

41 

45 

37 

41 

614 

00 

616 

151 

155 

101 

105 

75 

79 

59 

63 

49 

53 

41 

45 

37 

41 

616 

CD 

618 

153 

157 

101 

105 

75 

79 

59 

63 

49 

53 

43 

47 

37 

41 

618 

00 

620 

153 

157 

101 

105 

75 

79 

5'.) 

63 

49 

53 

43 

47 

37 

41 

620 

(5) 

622 

153 

157 

fill 

105 

75 

79 

61 

65 

49 

53 

43 

47 

37 

41 

622 

00 

624 

153 

157 

101 

105 

75 

79 

61 

65 

49 

53 

43 

47 

37 

41 

624 

GD 

626 

155 

159 

ll):5 

107 

77 

81 

61 

65 

51 

55 

43 

47 

37 

41 

626 

oo 

628 

155 

159 

103 

107 

77 

81 

61 

65 

51 

55 

43 

47 

37 

41 

628 

GD 

630 

155 

159 

103 

107 

77 

81 

61 

65 

51 

55 

43 

47 

37 

41 

630 

oo 

<;:i2 

155 

159 

103 

107 

77 

81 

(11 

65 

51 

55 

43 

47 

37 

41 

632 

QD. 

634 

157 

161 

103 

107 

77 

81 

61 

65 

51 

55 

43 

47 

37 

41 

634 

00 

636 

157 

161 

103 

107 

77 

81 

61 

65 

51 

55 

43 

47 

37 

41 

636 

GJB 

638 

157 

161 

105 

109 

77 

81 

61 

65 

51 

55 

43 

47 

37 

41 

638 

oo 

640 

157 

161 

105 

109 

77 

81 

61 

65 

51 

55 

43 

47 

37 

41 

640 

PJ3 

642 

159 

163 

105 

109 

79 

83 

63 

67 

51 

55 

43 

47 

39 

43 

642 

00 

644 

159 

i'6_3 

105 

109 

79 

83 

63 

67 

51 

55 

43 

47 

39 

43 

644 

© 

646 

159 

163 

105 

109 

79 

83 

63 

67 

51 

55 

45 

49 

39 

43 

646 

00 

648 

159 

163 

105 

109 

79 

83 

63 

67 

51 

55 

45 

49 

39 

43 

648 

GD 

650 

161 

165 

107 

111 

79 

83 

63 

67 

53 

57 

45 

49 

39 

43 

650 

00 

652 

161 

165 

107 

111 

79 

83 

63 

67 

53 

57 

45 

49 

39 

43 

652 

GD 

654 

161 

165 

107 

111 

79 

83 

63 

67 

53 

57 

45 

49 

39 

43 

654 

00 

656_ 

161 

165 

107 

111 

79 

83 

63 

(57 

53 

57 

45 

49 

39 

43 

656 

SSL- 

658 

163 

167 

107 

111 

81 

85 

63 

67 

53 

57 

45 

49 

39 

43 

658 

00 

660 

168 

167 

107 

111 

81 

85 

63 

67 

53 

57 

45 

49 

39 

43 

660 

GD 

662 

163 

167 

11)9 

113 

81 

85 

65 

69 

53 

57 

45 

49 

39 

43 

662 

oo 

664 

163 

167 

109 

113 

81 

85 

65 

69 

53 

57 

45 

49 

39 

43 

664 

GD 

666 

"  165 

161) 

10!) 

]  1  3 

81 

85 

65 

69 

53 

57 

45 

49 

39 

43 

666 

00 

668 

165 

169 

109 

113 

81 

85 

65 

69 

53 

57 

45 

49 

39 

43 

668 

GD 

670 

165 

169 

109 

113 

81 

85 

65 

69 

53 

57 

45 

49 

39 

43 

670 

oo 

672 

165 

169 

109 

113 

81 

85 

65 

69 

53 

57 

45 

49 

39 

43 

672 

ua 

674 

167 

171 

111 

115 

83 

87 

65 

69 

55 

59 

47 

51 

41 

45 

674 

00 

070 

167 

171 

111 

115 

88 

87 

65 

69 

55 

59 

47 

51 

41 

45 

676 

OQ 

678 

167 

171 

111 

115 

83 

87 

65 

69 

55 

59 

47 

51 

41 

45 

678 

00 

<;so 

167 

171 

111 

115 

83 

87 

65 

69 

55 

59 

47 

51 

41 

45 

680 

GD 

682 

169 

173 

111 

115 

83 

87 

67 

71 

55 

59 

47 

51 

41 

45 

682 

oo 

684 

169 

173 

111 

115 

83 

87 

67 

7i 

55 

59 

47 

51 

41 

45 

684 

GD 

686 

169 

173 

113 

117 

83 

87 

67 

71 

55 

59 

47 

51 

41 

45 

686 

oo 

688 

169 

173 

113 

117 

83 

87 

67 

71 

55 

59 

47 

51 

41 

45 

688 

GD 

690 

171 

175 

113 

117 

85 

89 

67 

71 

55 

59 

47 

51 

41 

45 

690 

oo 

692 

171 

175 

113 

117 

85 

89 

67 

71 

55 

59 

47 

51 

41 

45 

692 

GD 

694 

171 

175 

113 

117 

85 

89 

67 

71 

55 

59 

47 

51 

41 

45 

694 

oo 

096 

171 

175 

113 

117 

85 

89 

67 

71 

55 

5!) 

47 

51 

41 

45 

696 

GD 

Baa 

173 

177 

115 

119 

85 

89 

67 

71 

57 

61 

47 

51 

41 

45 

698 

oo 

700 

173 

177 

115 

119 

85 

89 

67 

71 

57 

61 

47 

51 

41 

45 

700 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute 
magnitude  of  average  p  tch  may  be  varied  within  reasonable  limits. 

5SI7BRSIT7 


MULTIPLE-CIRCUIT,  DOUBLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-ENTRANCY 

No.OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

No.  OF  CONDUCTORS 

4 

POLES 

6 

POLES 

8 

POLES 

10 
POLES 

12 
POLES 

14 

POLES 

16 

POLES 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

GD 

702 

173 

177 

115 

119 

85 

89 

69 

73 

57 

61 

49 

53 

41 

45 

702 

oo 

704 

173 

177 

115 

119 

85 

89 

69 

73 

57 

61 

49 

53 

41 

45 

704 

GD 

706 

175 

170 

115 

119 

87 

91 

CO 

73 

57 

61 

49 

53 

13 

47 

706 

oo 

708 

175 

179 

115 

119 

87 

91 

69 

73 

57 

61 

40 

53 

43 

47 

708 

GD 

710 

175 

179 

117 

121 

87 

91 

69 

73 

57 

61 

49 

53 

43 

47 

710 

oo 

712 

175 

179 

117 

121 

87 

91 

69 

73 

57 

61 

49 

53 

43 

47 

712 

GD 

714 

177 

181 

117 

121 

87 

91 

69 

73 

57 

61 

49 

53 

43 

47 

714 

oo 

716 

177 

181 

117 

121 

87 

91 

69 

73 

57 

61 

49 

53 

43 

47 

716 

GD 

718 

177 

181 

117 

121 

87 

91 

69 

73 

57 

61 

49 

53 

43 

47 

718 
720 

oo 

721) 

177 

LSI 

117 

121 

87 

91 

69 

73 

57 

61 

49 

53 

43 

47 

GD 

722 

179 

183 

119 

123 

89 

93 

71 

75 

59 

63 

49 

53 

43 

47 

722 

00 

724 

179 

183 

11!) 

123 

89 

93 

71 

75 

59 

63 

49 

53 

43 

47 

724 

GD 

726 

179 

183 

119 

123 

89 

93 

71 

75 

59 

63 

49 

53 

43 

47 

720 

oo 

728 

179 

183 

119 

123 

89 

93 

71 

75 

59 

63 

49 

53 

43 

47 

728 

GD 

730 

181 

185 

119 

123 

89 

93 

71 

75 

59 

63 

51 

55 

43 

47 

730 

oo 

732 

181 

185 

119 

123 

89 

93 

71 

75 

59 

63 

51 

55 

43 

47 

732 

GD 

734 

181 

185 

121 

125 

SO 

93 

71 

75 

59 

63 

51 

55 

43 

47 

734 

00 

736 

181 

185 

121 

125 

89 

93 

71 

75 

59 

63 

51 

66 

43 

47 

736 

GD 

738 

183 

187 

121 

125 

91 

95 

71 

75 

59 

63 

51 

55 

45 

49 

738 

00 

740 

183 

187 

121 

125 

91 

95 

71 

75    . 

59 

63 

51 

55 

45 

49 

740 

fflj 

742 

]83__ 

187 

121 

125 

91 

JBfi_ 

73 

77 

59 

63 

51 

55 

45 

49 

742 

oo 

744 

183 

187 

121 

125 

91 

95 

73 

77 

59 

63 

51 

55 

45 

49 

744 

GD 

746 

185 

189 

123 

127 

91 

95 

73 

77 

61 

65 

51 

55 

45 

49 

74i; 

00 

748 

185 

189 

123 

127 

91 

95 

73 

77 

61 

65 

51 

55 

45 

49 

748 

GD 

750 

185 

189 

123 

127 

91 

95 

73 

77 

61 

65 

51 

55 

45 

49 

750 

oo 

752 

185 

189 

123 

127 

91 

95 

73 

77 

61 

65 

51 

55 

45 

49 

752 

GD 

754 

187 

191 

123 

127 

93 

97 

73 

77 

61 

65 

51 

55 

45 

49 

754 

oo 

756 

187 

191 

123 

127 

93 

97 

73 

77 

61 

65 

51 

55 

45 

49 

J5JS 

GD 

758 

187 

191 

125 

129 

93 

97 

73 

77 

61 

65 

53 

57 

45 

49 

758 

00 

760 

187 

191 

125 

129 

93 

97 

73 

77 

61 

65 

53 

57 

45 

49 

760 

CD 

762 

189 

193 

125 

129 

93 

97 

75 

79 

61 

65 

53 

57 

45 

49 

762 

oo 

764 

189 

193 

125 

129 

93 

97 

75 

79 

61 

65 

53 

57 

45 

49 

764 

GD 

766 

ISO 

193 

125 

129 

93 

97 

75 

79 

61 

65 

53 

57 

45 

49 

766 

oo 

768 

189 

193 

125 

129 

93 

97 

75 

79 

61 

65 

53 

57 

45 

49 

768 

GD 

770 

191 

195 

127 

131 

95 

99 

75 

79 

63 

67 

53 

57 

47 

51 

770 

oo 

_772 

191 

195 

127 

131 

95 

99 

75 

79 

63 

67 

53 

57 

47 

51 

772 

GO 

774 

191 

195 

127 

131 

95 

99 

75 

79 

88 

67 

53 

57 

47 

51 

774 

oo 

776 

191 

195 

127 

131 

95 

99 

75 

79 

68 

67 

53 

57 

47 

5J 

776 

GD 

778 

193 

197 

127 

131 

95 

99 

75 

79 

63 

67 

53 

57 

47 

51 

778 

oo 

780 

193 

197 

127 

131 

95 

99 

75 

79 

63 

67 

53 

57 

47 

61 

780 

GD 

782 

193 

197 

129 

133 

95 

99 

77 

81 

63 

67 

53 

57 

47 

51 

782 

00 

784 

193 

197 

129 

133 

95 

99 

77 

81 

63 

67 

53 

57 

47 

51 

784 

GD 

786 

195 

199 

129 

133 

97 

101 

77 

81 

63 

67 

55 

59 

47 

51 

786 

oo 

788 

195 

199 

129 

133 

07 

101 

77 

81 

63 

67 

55 

59 

47 

51 

788 

GD 

790 

195 

199 

129 

133 

97 

101 

77 

81 

63 

67 

55 

59 

47 

51 

790 

00 

792 

195 

199 

120 

133 

97 

101 

77 

81 

63 

67 

55 

59 

47 

51 

792 

GD 

794 

197 

201 

131 

135 

97 

101 

77 

81 

65 

69 

55 

59 

47 

51 

794 

oo 

796 

197 

201 

131 

135 

97 

101 

77 

81 

65 

(10 

55 

_jsa 

47 

51 

796 

GD 

798 

197 

201 

131 

135 

97 

101 

77 

81 

65 

69 

55 

59 

47 

51 

798 

00 

800 

197 

201 

131 

135 

97 

101 

77 

81 

65 

69 

55 

59 

47 

51 

800 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute 
magnitude  of  average  pitch  may  be  varied  within  reasonable  limits, 

MULTIPLE-CIRCUIT,  DOUBLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-ENTRANCY 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

CO 

• 

4 

POLES 

6 
POLES 

8 
POLES 

10 

POLES 

12 
POLES 

14 
POLES 

16 

POLES 

F 

B 

F 

B 

F 

B 

F 

B 

F 

.B 

F 

B 

F 

B 

o 

d 

z 

GD 

802 

199 

203 

131 

135 

99 

103 

79 

83 

65 

69 

55 

59 

49 

53 

802 

00 

804 

199 

203 

131 

135 

99 

103 

79 

83 

65 

69 

55 

59 

49 

53 

804 

GD. 

806 

199 

203 

133 

137 

99 

103 

79 

83 

65 

69 

55 

59 

49 

53 

806 

oo 

808 

199 

203 

133 

137 

99 

103 

79 

83 

65 

69 

55 

59 

49 

53 

808 

GD 

810 

201 

205 

133 

137 

99 

103 

79 

83 

65 

69 

55 

59 

49 

53 

810 

oo 

812 

201 

205 

133 

137 

99 

103 

79 

83 

65 

69 

55 

59 

49 

53 

812 

GO 

814 

201 

205 

133 

137 

99 

103 

79 

83 

65 

69 

57 

61 

49 

53 

814 

oo 

§16 

201 

205 

133 

137 

99 

103 

79 

83 

65 

69 

57 

61 

49 

53 

816 

GO 

818 

203 

207 

135 

139 

101 

105 

79 

83 

67 

71 

57 

61 

49 

53 

818 

oo 

820 

203 

207 

135 

139 

101 

105 

79 

83 

67 

71 

57 

81 

49 

53 

820 

GD 

822 

203 

207 

135 

139 

101 

105 

81 

85 

67 

71 

57 

61 

49 

53 

822 

00 

824 

203 

207 

135 

139 

Jfoi 

105 

81 

85 

67 

71 

57 

61 

49 

53 

824 

GD 

826 

205 

209 

135 

139 

101 

105 

81 

85 

67 

71 

57 

61 

49 

53 

826 

00 

828 

205 

209 

135 

139 

101 

105 

81 

85 

67 

71 

57 

(11 

49 

53 

828 

GD 

830 

205 

209 

137 

141 

101 

105 

81 

85 

67 

71 

57 

61 

49 

53 

830 

00 

832 

200 

209 

137 

141 

101 

105 

81 

85 

67 

71 

57 

61 

-49 

53 

832 

GD 

834 

207 

211 

137 

141 

103 

107 

81 

85 

67 

71 

57 

61 

51 

55 

834 

oo 

836 

207 

211 

137 

141 

103 

107 

81 

85 

67 

71 

57 

61 

51 

55 

836 

GD 

838 

207 

211 

137 

141 

103 

107 

81 

85 

67 

71 

57 

61 

51 

55 

838 

oo 

840 

207 

211 

137 

141 

103 

107 

81 

85 

67 

71 

57 

61 

51 

55 

840 

GD 

842 

209 

213 

139 

143 

103 

107 

83 

87 

69 

73 

59 

63 

51 

55 

842 

oo 

844 

209 

213 

139 

143 

103 

107 

83 

87 

69 

73 

59 

63 

51 

55 

844 

GD 

846 

209 

213 

139 

143 

103 

107 

83 

87 

69 

73 

59 

(13 

51 

55 

846 

oo 

848 

209 

213 

139 

143 

103 

107 

83 

87 

69 

73 

59 

63 

51 

55 

848 

GD 

850 

211 

215 

139 

143 

105 

109 

83 

87 

69 

73 

59 

63 

51 

55 

850 

00 

852 

211 

215 

139 

143 

105 

109 

83 

87 

69 

73 

59 

63 

51 

55 

852 

GD 

854 

211 

215 

141 

145 

105 

109 

83 

87 

69 

73 

59 

63 

51 

55 

854 

00 

856 

211 

215 

111 

145 

105 

109 

83 

87 

69 

73 

59 

63 

51 

55 

856 

GD 

858 

213 

217 

141 

145 

105 

109 

83 

87 

69 

73 

69 

63 

51 

55 

858 

oo 

860 

213 

217 

141 

145 

105 

109 

83 

87 

69 

73 

59 

63 

51 

55 

860 

GD 

862 

213 

217 

141 

145 

105 

109 

85 

89 

69 

73 

59 

63 

51 

55 

862 

oo 

864 

213 

217 

141. 

145 

105 

109 

85 

89 

69 

73 

59 

63 

51 

55 

864 

GD 

8liG 

215 

219 

143 

147 

107 

111 

85 

89 

71 

75 

59 

63 

53 

57 

866 

00 

8(>8 

215 

219 

143 

147 

107 

111 

85 

89 

71 

75 

59 

63 

53 

57 

868 

(S3 

870 

215 

219 

143 

147 

107 

111 

85 

89 

71 

75 

61 

65 

53 

57 

870 

00 

872 

215 

219 

143 

147 

107 

111 

85 

89 

71 

75 

61 

65 

53 

57 

872 

GD 

874 

217 

221 

143 

147 

107 

111 

85 

89 

71 

75 

61 

65 

53 

57 

874 

00 

876 

217 

221 

143 

147 

107 

111 

85 

89 

71 

75 

61 

65 

53 

57 

876 

GD 

878 

217 

221 

145 

149 

107 

111 

85 

89 

71 

75 

61 

65 

53 

57 

878 

00 

880 

217 

221 

145 

149 

107 

111 

85 

89 

71 

75 

61 

65 

53 

57 

880 

GD 

882 

219 

223 

145 

149 

109 

113 

87 

91 

71 

75 

61 

65 

53 

57 

882 

oo 

884 

219 

223 

115 

149 

109 

113 

87 

91 

71 

75 

61 

65 

53 

57 

884 

GD 

88(3 

219 

223 

145 

149 

_109 

113 

87 

91 

71 

75 

61 

G5 

53 

57 

886 

oo 

888 

219 

223 

115 

149 

109 

113 

87 

91 

71 

75 

61 

65 

53 

57 

888 

GD 

890 

221 

225 

147 

151 

109 

113 

87 

91 

73 

77 

61 

65 

53 

57 

890 

oo 

892 

221 

225 

147 

151 

109 

113 

87 

91 

73 

77 

61 

65 

53 

57 

892 

GD 

894 

221 

225 

147 

151 

1  09 

113 

87 

91 

73 

77 

61 

65 

53 

57 

894 

00 

896 

221 

225 

147 

151 

109 

113 

87 

91 

73 

77 

61 

65 

53 

57 

896 

GD 

898 

223 

227 

147 

151 

111 

115 

87    . 

91 

73 

77 

63 

67 

55 

59 

898 

oo 

900 

223 

227 

147 

151 

111 

115    | 

87 

91 

73 

77 

63 

67 

55 

59 

900 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although;,  as  stated  in  text,  the  absolute 
magnitude  of  average  pitch  may  be  varied  within  reasonable  limits. 

- 

MULTIPLE-CIRCUIT,  DOUBLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-ENTRANCY 

No.OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

CO 

cc 
o 

4 

POLES 

6 
POLES 

8 

POLES 

10 

POLES 

12 
POLES 

14 

POLES 

16 

POLES 

CON  DUG! 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

O 

o 

•Z 

CE> 

902 

223 

227 

149 

153 

in 

115 

89 

93 

73 

77 

63 

67 

55 

59 

902 

oo 

904 

223 

227 

149 

153 

in 

115 

89 

93 

73 

77 

63 

67 

55 

59 

904 

CS3 

906 

225 

229 

149 

153 

in 

115 

89 

1)3 

73 

77 

63 

67 

55 

59 

906 

00 

908 

225 

229 

149 

153 

in 

115 

89 

93 

73 

77 

63 

67 

55 

59 

908 

(33 

910 

225 

229 

149 

153 

in 

115 

89 

93 

73 

77 

63 

67 

55 

59 

910 

oo 

912 

225 

229 

149 

153 

in 

115 

89 

93 

73 

77 

63 

67 

55 

59 

912 

Cfl) 

911 

227 

231 

151 

155 

113 

117 

89 

93 

75 

79 

63 

67 

55 

59 

914 

oo 

916 

227 

231 

151 

155 

113 

117 

89 

93 

75 

79 

63 

67 

55 

59 

916 

QD 

918 

227 

231 

151 

155 

113 

11.7 

89 

93 

75 

79 

63 

67 

55 

59 

918 

oo 

920 

227 

231 

151 

155 

113 

1171 

89 

93 

75 

79 

63 

67 

55 

59 

920 

0 

922 

229 

233 

151 

155 

113 

117 

91 

95 

75 

79 

03 

67 

55 

59 

922 

oo 

924 

221) 

233 

151 

155 

113 

117 

91 

95 

75 

79 

63 

67 

55 

59 

924 

O 

926 

229 

233 

153 

157 

,113 

11.7 

91 

95 

75 

79 

65 

69 

55 

59 

926 

00 

928 

229 

233 

153 

157 

113 

117 

91 

95 

75 

79 

65 

69 

55 

59 

928 

C5> 

930 

231 

235 

153 

157 

115 

119 

91 

95 

75 

79 

65 

69 

57 

61 

930 

oo 

932 

231 

235 

153 

157 

115 

119 

91 

95 

75 

79 

65 

69 

57 

61 

932 

C5D 

934 

231 

235 

153 

157 

115 

119 

91 

95 

75 

79 

65 

69 

57 

61 

934 

oo 

936 

231 

235 

153 

157 

115 

119 

91 

95 

75 

79 

65 

69 

57 

01 

930 

CE> 

938 

233 

237 

155 

159 

115 

119 

91 

95 

77 

81 

65 

01) 

57 

61 

938 

oo 

940 

233 

237 

155 

159 

115 

119 

91 

95 

77 

81 

65 

69 

57 

61 

940 

(2) 

942 

233 

_237 

155 

159 

115 

.119 

93 

97 

77 

81 

65 

69 

57 

61 

942 

oo 

944 

233 

_237 

155 

159 

115 

119 

93 

97 

77 

81 

65 

69 

57 

61 

944 

CE> 

940 

235 

239 

155 

159 

117 

121 

93 

97 

77 

81 

65 

69 

57 

61 

946 

oo 

948 

235 

239 

155 

159 

117 

121 

93 

97 

77 

81 

65 

Oil 

57 

61 

948 

CS) 

950 

235 

239 

157 

161 

117 

121 

93 

97 

77 

81 

65 

0!) 

57 

61 

950 

oo 

952 

235 

239 

157 

161 

117 

121 

_tt 

97 

77 

81 

65 

01) 

57 

61 

952 

CE> 

954 

237 

241 

157 

161 

117 

121 

1)3 

97 

77 

81 

67 

71 

57 

61 

954 

oo 

956 

237 

241 

157 

161 

117 

121 

1)3 

97 

77 

81 

67 

71 

57 

61 

956 

C5) 

958 

237 

241 

157 

161 

117 

121 

93 

97 

77 

81 

67 

71 

57 

61 

958 

oo 

960 

237 

241 

157 

161 

117 

121 

1)3 

97 

77 

81 

67 

71 

57 

61. 

960 

CE> 

962 

239 

243 

159 

163 

119 

123 

95 

99 

79 

83 

67 

71 

59 

63 

962 

00 

964 

239 

243 

159 

163 

119 

123 

95 

99 

79 

83 

67 

71 

59 

63 

964 

CE> 

966 

239 

243 

.159 

103 

119 

123 

95 

99 

79 

83 

67 

71 

59 

63 

966 

oo 

968 

^239 

243 

159 

163 

119 

123 

95 

99 

79 

83 

67 

71 

59 

63 

968 

CE> 

970 

241 

245 

159 

163 

119 

123 

95 

99 

79 

83 

67 

71 

59 

63 

970 

oo 

972 

241 

245 

159 

163 

119 

123 

95 

99 

79 

83 

67 

71 

59 

63 

972 

® 

974 

241 

245 

161 

165 

119 

123 

95 

99 

79 

83 

67 

71 

59 

63 

974 

oo 

970 

241 

245 

161 

165 

119 

123 

95 

99 

79 

83 

67 

71 

59 

63 

976 

CE> 

978 

243 

247 

101 

165 

121 

125 

95 

99 

79 

83 

67 

71 

51) 

03 

978 

oo 

980 

243 

247 

J01 

165 

121 

125 

95 

99 

79 

S3 

67 

71 

59 

63 

980 

C5J 

982 

243 

247 

161 

165 

121 

125 

97 

101 

79 

83 

69 

73 

59 

63 

982 

00 

984 

243 

247 

161 

165 

121 

125 

97 

101 

79 

83 

69 

73 

59 

63 

984 

O 

980 

245 

249 

163 

167 

121 

125 

97 

101 

81 

85 

01) 

73 

51) 

63 

980 

oo 

988 

245 

249 

103 

167 

121 

125 

97 

101 

81 

85 

01) 

73 

59 

63 

988 

00 

990 

245 

249 

163 

1671 

121 

125 

97 

101 

81 

85 

69 

73 

59 

63 

990 

oo 

992 

245 

.249 

163 

167 

121 

125 

97 

101 

81 

85 

69 

73 

59 

63 

992 

CE> 

994 

247 

251 

163 

167 

123 

:27 

97 

101 

81 

85 

69 

73 

61 

65 

994 

oo 

996 

247 

251 

J63 

167 

.123 

:27 

97 

101 

81 

85 

69 

73 

61 

65 

990 

CD 

998 

247. 

251 

165 

169 

123 

{27 

97 

101 

81 

85 

69 

73 

01 

65 

998 

oo 

1000 

247 

251 

165 

169 

123 

127 

97 

101 

81 

85 

69 

73 

61 

65 

1000 

Above  choice  of  PHches  will  prove  roost  satisfactory,  although,  as  stated  in  text,  the  absolute 
rnagnttouda  of  average.  pHjch  may  be  varied  within  reasonable  Emits. 

MULTIPLE-CIRCUIT,  DOUBLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-ENTRANCY 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

CO 

• 
o 

4 

POLES 

6 
POLES 

8 

POLES 

10 

POLES 

12 
POLES 

14 

POLES 

16 
POLES 

CON'DUC" 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

o 

d 

Z 

GO 

1002 

249 

253 

165 

169 

123 

127 

99 

103 

81 

85 

69 

73 

61 

65 

1002 

00 

1004 

249 

253 

165 

169 

123 

127 

99 

103 

81 

85 

69 

73 

61 

65 

1004 

go 

1006 

249 

253 

165 

169 

123 

127 

99 

103 

81 

85 

69 

73 

61 

§6 

1000 

oo 

1008 

249 

253 

165 

169 

123 

127 

99 

103 

81 

85 

69 

73 

<;i 

65 

1008 

GD 

1010 

251 

255 

167 

171 

125 

129 

99 

103 

83 

87 

71 

75 

61 

65 

1010 

oo 

1012 

~55l 

255 

167 

171 

125 

129 

99 

103 

S3 

87 

71 

75 

61 

65 

!  1012 

GD 

1014 

251 

255 

167 

171 

125 

129 

99 

103 

83 

87 

71 

75 

61 

65 

i  1014 

oo 

1016 

251 

255 

167 

171 

125 

129 

99 

103 

83 

87 

71 

75 

61 

65 

1016 

GO 

1018 

253 

257 

167 

171 

125 

129 

99 

103 

83 

87 

71 

75 

61 

65 

1018 

oo 

1020 

253 

257 

167 

171 

125 

129 

99 

103 

83 

87 

71 

75 

61 

65 

1020 

GD 

1022 

253 

257 

169 

173 

125 

129 

101 

105 

83 

87 

71 

75 

61 

65 

1022 

oo 

1024 

253 

257 

169 

173 

125 

129 

101 

105 

83 

87 

71 

75 

61 

65 

|  1024 

GO 

1020 

255 

259 

169 

173 

127 

131 

101 

105 

83 

87 

71 

75 

63 

67 

1026 

oo 

1028 

255 

259 

169 

173 

127 

131 

101 

105 

83 

87 

71 

75 

63 

67 

1028 

GD 

1030 

255 

259 

169 

173 

127 

131 

101 

105 

83 

87 

71 

75 

63 

67 

1030 

oo 

1032 

255 

259 

169 

173 

127 

131 

101 

105 

83 

87 

71 

75 

68 

67 

1032 

GD 

10:54 

257 

261 

171 

175 

127 

131 

101 

105 

85 

89 

71 

75 

63 

67 

1034 

00 

1036 

257 

261 

171 

175 

127 

131 

101 

105 

85 

89 

71 

75 

63 

67 

10.36 

GD 

1038 

257 

261 

171 

175 

127 

131 

101 

105 

85 

89 

73 

77 

63 

67 

1038 

00 

1010 

257 

261 

171 

175 

127 

131 

101 

105 

85 

89 

73 

77 

63 

67 

1040 

GD 

1042 

259 

263 

171 

175 

129 

133 

103 

107 

85 

89 

73 

77 

BJ 

67 

1042 

oo 

1044 

259 

263 

171 

175 

129 

133 

103 

107 

85 

89 

73 

77 

63 

67 

1044 

GD 

1046 

259 

263 

173 

177 

129 

133 

103 

107 

85 

89 

73 

77 

63 

67 

1046 

00 

1048 

259 

263 

173 

177 

129 

133 

103 

107 

85 

89 

73 

77 

63 

67 

1048 

GD 

1050 

261 

265 

173 

177 

129 

133 

103 

107 

85 

89 

73 

77 

63 

67 

1050 

00 

]  052 

261 

265 

173 

177 

129 

133 

103 

107 

85 

89 

73 

77 

63 

67 

1052 

GD 

1054 

261 

265 

173 

177 

129 

133 

103 

107 

85 

89 

73 

77 

63 

67 

1054 

oo 

1056 

261 

265 

173 

177 

129 

133 

103 

107 

85 

89 

73 

77 

63 

67 

1056 

GD 

1058 

263 

267 

175 

179 

131 

135 

103 

107 

87 

91 

73 

77 

65 

69 

1058 

00 

]()60 

263 

267 

175 

179 

131 

186 

103 

107 

87 

91 

73 

77 

65 

69 

1060 

GD 

1062 

263 

267 

175 

179 

131 

135 

105 

109 

87 

91 

73 

77 

65 

69 

10I12 

oo 

1064 

263 

267 

175 

179 

131 

135 

105 

109 

87 

91 

73 

77 

65 

69 

1064 

GD 

1066 

265 

269 

175 

179 

131 

135 

105 

109 

87 

91 

75 

79 

65 

69 

1066 

oo 

1068 

265 

269 

175 

179 

131 

135 

105 

109 

87 

91 

75 

79 

65 

69 

1068 

GD 

1070 

265 

269 

177 

181 

131 

135 

105 

109 

87 

91 

75 

79 

65 

69 

1070 

00 

1072 

265 

269 

177 

181 

131 

135 

105 

109 

'  87 

1)1 

75 

79 

65 

69 

1072 

GD 

1074 

267 

271 

177 

181 

133 

137 

105 

109 

87 

91 

75 

79 

65 

69 

1074 

00 

1076 

267 

271 

177 

181 

133 

137 

105 

109 

87 

91 

75 

79 

65 

69 

1076 

GO 

1  078 

267 

271 

177 

181 

133 

137 

105 

109 

87 

91 

75 

79 

65 

69 

1078 

00 

1080 

267 

271 

177 

181 

133 

137 

105 

109 

87 

91 

75 

79 

65 

69 

1080 

GO 

1  082 

269 

273 

179 

183 

133 

137 

107 

111 

89 

93 

75 

79 

65 

69 

1082 

00 

1084 

269 

273 

179 

183 

133 

137 

107 

111 

81) 

93 

75 

79 

65 

69 

1084 

GD 

lose, 

269 

273 

171) 

183 

133 

137 

107 

111 

89 

93 

75 

79 

65 

69 

1086 

00 

108H 

269 

273 

179 

183 

133 

137 

107 

111 

82 

93 

75 

79 

65 

69 

loss 

GD 

101)0 

271 

275 

179 

183 

135 

139 

107 

111 

89 

93 

75 

79 

67 

71 

1090 

oo 

101)2 

271 

275 

179 

183 

135 

139 

107 

111 

89 

93 

75 

79 

67 

71 

1092 

GO 

1094 

271 

275 

181 

185 

135 

139 

107 

111 

89 

93 

77 

81 

67 

71 

1094 

oo 

1096 

271 

275 

181 

185 

135 

139 

107 

111 

89 

93 

77 

81 

67 

71 

1096 

GD 

1098 

273 

277 

181 

185 

135 

139 

107 

111 

89 

93 

77 

81 

67 

71 

109S 

0  O 

1100 

273 

277 

181 

185 

135 

139 

107 

111 

89 

93 

77 

81 

67 

71 

1100 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute 
magnitude  of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  DOUBLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-ENTRANCY 

No.OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

No.OF  CONDUCTORS 

4 
POLES 

6 

POLES 

8 

POLES 

10 

POLES 

12 
POLES 

14 

POLES 

16 

POLES 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

(53 

1102 

273 

277 

181 

185 

135 

139 

109 

113 

89 

93 

77 

81 

67 

71 

1102 

oo 

not 

273 

277 

181 

185 

135 

139 

109 

113 

89 

93 

77 

81 

67 

71 

1104 

© 

1106 

275 

279 

183 

187 

137 

141 

109 

113 

91 

95 

77 

81 

67 

71 

1106 

oo 

1108 

275 

279 

183 

187 

137 

141 

109 

113 

91 

95 

77 

81 

67 

71 

1108 

C2> 

1110 

275 

279 

183 

187 

137 

141 

109 

113 

91 

95 

77 

81 

67 

71 

1110 

00 

1112 

275 

279 

183 

187 

137 

141 

109 

113 

91 

95 

77 

81 

67 

71 

1112 

CE> 

1114 

277 

281 

183 

187 

137 

141 

109 

113 

91 

95 

77 

.    81 

67 

71 

1114 

oo 

1116 

277 

281 

is:', 

187 

137 

141 

109 

113 

91 

95 

77 

81 

67 

71 

1116 

CE> 

1118 

277 

281 

185 

189 

137 

141 

109 

113 

91 

95 

77 

81 

67 

71 

1118 

oo 

1  120 

277 

281 

185 

189 

137 

141 

109 

113 

91 

95 

77 

81 

67 

71 

1120 

CE> 

1122 

279 

283 

185 

189 

139 

143 

111 

115 

91 

95 

79 

83 

69 

73 

1122 

00 

1124 

279 

283 

185 

189 

139 

143 

111 

115 

91 

95 

79 

83 

69 

73 

1124 

C53 

1126 

279 

283 

isr, 

1  89 

139 

113 

111 

115 

91 

95 

79 

83 

69 

73 

1126 

oo 

1128 

279 

283 

185 

189 

139 

143 

111 

115 

91 

95 

79 

83 

69 

73 

1128 

(5) 

i  i:jo 

281 

285 

187 

191 

139 

143 

111 

115 

93 

97 

79 

83 

69 

73 

1130 

00 

L132 

281 

285 

187 

191 

139 

143 

111 

115 

93 

97 

79 

88 

69 

73 

1132 

(33 

1134 

281 

285 

187 

191 

139 

143 

1    111 

115 

93 

97 

79 

83 

69 

73 

1134 

o  o 

USfi 

281 

ass 

187 

191 

139_ 

143 

111 

115 

93 

97 

79 

83 

_fia  _ 

73 

1136 

Co) 

1138 

288 

287 

187 

191 

141 

145 

111 

115 

93 

97 

79 

83 

69 

73 

1138 

oo 

UK) 

288 

287 

187 

191 

141 

145 

111 

115 

93 

97 

79 

83 

69 

73 

1140 

C53 

1142 

283 

287 

189 

193 

141 

145 

113 

117 

93 

97 

79 

83 

69 

73 

1142 

oo 

1  Hi 

283 

287 

189 

193 

141 

145 

113 

117 

93 

97 

79 

83 

69 

73 

1144 

CE> 

1146 

285 

289 

1S9 

193 

141 

145 

113 

117 

93 

97 

79 

83 

.  82_ 

73 

1146 

oo 

IMS 

285 

289 

189 

193 

141 

145 

113 

117 

93 

97 

79 

S3 

69 

73 

1148 

C53 

1150 

285 

289 

189 

193 

141 

145 

113 

117 

93 

97 

81 

85 

69 

73 

1150 

O  0 

1152 

285 

289 

189 

193 

141 

145 

113 

117 

93 

97 

81 

85 

69 

73 

1152 

o 

1154 

287 

•291 

191 

195 

143 

147 

113 

117 

95 

99 

81 

85 

71 

75 

1154 

oo 

1156 

287 

291 

191 

195 

143 

147 

113 

117 

95 

99 

81 

85 

71 

75 

1156 

CE> 

1158 

287 

•291 

191 

195 

143 

147 

113 

117 

95 

99 

81 

85 

71 

75 

1158 

oo 

1160 

287 

291 

191 

195 

143 

147 

113 

117 

95 

99 

81 

85 

71 

75 

1160 

(5) 

1162 

289 

293 

191 

195 

143 

147 

115 

119 

95 

99 

81 

85 

71 

75 

1162 

oo 

1164 

289 

293 

191 

195 

143 

147 

115 

119 

95 

99 

81 

85 

71 

75 

1164 

CE> 

1166 

289 

29:', 

193 

197 

143 

147 

115 

119 

95 

99 

81 

85 

71 

75 

1166 

oo 

1168 

289 

293 

193 

197 

143 

147 

115 

119 

95 

99 

81 

85 

71 

75 

1168 

CE> 

1170 

291 

295 

193 

197 

145 

149 

115 

119 

95 

99 

81 

85 

71 

75 

1170 

oo 

1172 

291 

295 

193 

197 

145 

149 

115 

119 

95 

99 

81 

85 

71 

75 

1172 

(5) 

1174 

291 

295 

193 

197 

145 

149 

115 

119 

95 

99 

81 

85 

71 

75 

1174 

oo 

1176 

291 

295 

193 

197 

145 

149 

115 

119 

95 

99 

81 

85 

71 

75 

1176 

© 

1178 

293 

297 

195 

199 

145 

149 

115 

119 

97 

101 

83 

87 

71 

75 

1.178 

00 

USD 

293 

297 

195 

199 

145 

149 

115 

119 

97 

101 

83 

87 

71 

75 

1180 

© 

1182 

293 

297 

195 

199 

145 

149 

117 

121 

97 

101 

83 

K7 

71 

75 

1182 

1  1  Si 

293 

•297 

195 

199 

145 

149 

117 

121 

97 

101 

83 

87 

71 

75 

1184 

© 

1186 

295 

299 

195 

199 

147 

151 

117 

121 

97 

101 

83 

87 

73 

77 

1186 

00 

1188 

295 

299 

195 

199 

147 

151 

117 

m 

97 

101 

83 

87 

73 

77 

1188 

GO 

1190 

295 

299 

197 

201 

147 

151 

117 

121 

97 

101 

83 

87 

73 

77 

1190 

oo 

11112 

295 

299 

197 

201 

147 

151 

117 

121 

97 

101 

83 

87 

73 

77 

1192 

CD 

111  )•! 

•I'M 

301 

197 

21)1 

147 

151 

117 

121 

97 

101 

83 

87 

73 

77 

1194 

oo 

11  IK; 

297 

301 

197 

201 

147 

151 

117 

121 

97 

101 

83 

87 

73 

77 

1196 

3D 

11!»S 

297 

301 

197 

201 

147 

151 

117 

121 

97 

101 

83 

87 

73 

77 

1198 

oo 

1200 

297 

301 

197 

201 

147 

151 

117 

121 

97 

101 

83 

87 

73 

77 

1200 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute 
magnitude  of  average  pitch  may  be  varied  wfthin  reasonable  limits. 

MULTIPLE-CIRCUIT,  DOUBLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-FNTRANCY 

No.OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

CO 

cc 
o 

4 

POLES 

6 

POLES 

8 

POLES 

10 

POLES 

12 
POLES 

14 
POLES 

16 

POLES 

CONDUCl 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

IL 

O 
6 

Z 

GD 

1202 

299 

303 

199 

203 

149 

153 

119 

123 

99 

103 

83 

87 

73 

77 

1202 

oo 

1204 

299 

303 

199 

203 

149 

153 

119 

123 

99 

103 

§3 

87 

73 

77 

1204 

so 

1206 

299 

308 

199 

203 

149 

153 

119 

123 

99 

103 

85 

89 

73 

77 

1206 

oo 

1208 

299 

303 

199 

203 

149 

153 

119 

123 

9!) 

103 

85 

89 

73 

77 

1208 

CD 

1210 

301 

305 

199 

203 

149 

153 

119 

123 

99 

108 

85 

89 

73 

77 

1210 

00 

1212 

301 

305 

199 

203 

149 

153 

119 

123 

99 

103 

85 

89 

73 

77 

1212 

GD 

1214 

301 

305 

201 

205 

149 

153 

119 

123 

99 

103 

85 

89 

73 

77 

1214 

00 

1216 

301 

305 

201 

205 

149 

153 

119 

123 

99 

103 

85 

89 

73 

77 

1216 

GD 

1218 

303 

307 

201 

205 

151 

155 

119 

123 

99 

103 

85 

89 

75 

79 

1218 

00 

1220 

:;n.; 

307 

201 

205 

151 

155 

119 

123 

99 

103 

85 

89 

75 

79 

1220 

GD 

1222 

303 

307 

201 

205 

151 

155 

121 

125 

99 

103 

85 

89 

75 

79 

1222 

oo 

1224 

81):! 

307 

201 

205 

151 

155 

121 

125 

99 

103 

85 

89 

75 

79 

1221 

GD 

1226 

305 

309 

203 

207 

151 

155 

121 

125 

101 

105 

85 

89 

75 

79 

1226 

oo 

1228 

805 

30'.) 

203 

207 

151 

155 

,  121 

125 

101 

105 

85 

89 

75 

79 

1228 

32 

1230 

305 

809 

203 

207 

151 

155 

121 

125 

101 

105 

85 

89 

75 

79 

1230 

.   00 

1232 

305 

309 

203 

207 

151 

155 

121 

_125 

101 

105 

85 

89 

75 

79 

1232 

GD 

1234 

307 

311 

203 

207 

153 

157 

121 

125 

101 

105 

87 

91 

75 

79 

1234 

00 

1236 

307 

311 

203 

207 

153 

157 

121 

125 

101 

105 

87 

91 

75 

79 

1236 

GD 

1238 

307 

311 

205 

209 

153 

157 

121 

125 

101 

105 

87 

91 

75 

79 

1238 

00 

1240 

307 

311 

205 

209 

153 

157 

121 

125 

101 

105 

87 

91 

75 

79 

1240 

_GD_ 

00 

1242 

309 

313 

205 

209 

153 

157 

123 

127 

101 

105 

87 

91 

75 

79 

1242 

1244 

8Q2 

313 

205 

209 

153 

157 

123 

.1  2i_ 

101 

105 

.   87. 

91 

75 

79 

1244 

£52 

124fi 

309 

313 

205 

209 

153 

157 

123 

127 

101 

105 

87 

91 

75 

79 

12  tO 

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1248 

309 

313 

205 

209 

153 

157 

123 

127 

101 

105 

87 

91 

75 

79 

1248 

GD 

1250 

311 

315 

207 

211 

155 

159 

123 

127 

103 

107 

87 

91 

77 

81 

1250 

00 

1252 

311 

315 

207 

211 

155 

159 

123 

127 

103 

107 

87 

91 

77 

81 

1252 

GD 

1254 

311 

315 

207 

211 

155 

159 

123 

127 

103 

107 

87 

91 

77 

81 

1254 

00 

1256 

311 

315 

207 

211 

155 

159 

123 

127 

103 

107 

87 

91 

77 

81 

1250 

GD 

1258 

313 

317 

207 

211 

155 

159 

123 

127 

103 

107 

87 

91 

77 

81 

1258 

00 

1260 

313 

317 

207 

211 

155 

159 

123 

127 

103 

107 

87 

91 

77 

81 

1260 

GD 

12(12 

313 

317 

209 

213 

155 

159 

125 

129 

103 

107 

89 

93 

77 

81 

1262 

00 

12G4 

313 

317 

209 

213 

155 

159 

125 

122 

103 

107 

89 

93 

77 

81 

1264 

GD 

1266 

315 

319 

209 

213 

157 

161 

125 

129 

103 

107 

89 

93 

77    ' 

81 

1266 

00 

126S 

815 

319 

209 

213 

157 

161 

125 

129 

103 

107 

89 

93 

77 

81 

1268 

GD 

1270 

315 

319 

209 

213 

157 

161 

125 

129 

103 

107 

89 

93 

•77 

81 

1270 

00 

1272 

315 

319 

209 

213 

157 

161 

125 

129 

103 

107 

89 

93 

77 

81 

1272 

GD 

1274 

317 

321 

211 

215 

157 

161 

125 

129 

105 

109 

89 

93 

77 

81 

1274 

oo 

1270 

317 

321 

211 

215 

157 

161 

125 

129 

105 

109 

89 

93 

77 

81 

1276 

GD 

1278 

317 

321 

211 

215 

157 

161 

125 

129 

105 

109 

89 

93 

77 

81 

1278 

00 

1280 

317 

321 

211 

215 

157 

161 

125 

129 

105 

109 

89 

93 

77 

81 

1  280 

GD 

1282 

319 

323 

211 

215 

159 

163 

127 

131 

105 

109 

89 

93 

79 

83 

1282 

00 

1284 

319 

323 

211 

215 

159 

163 

127 

131 

105 

109 

89 

93 

79 

88 

1284 

GD 

1286 

319 

323 

213 

217 

159 

163 

127 

131 

105 

109 

89 

93 

79 

83 

1286 

00 

I  288 

319 

323 

213 

217 

159 

163 

127 

131 

105 

109 

89 

93 

79 

83 

1288 

GD 

1290 

321 

325 

213 

217 

159 

163 

127 

131 

105 

109 

91 

95 

79 

83 

1290 

00 

1292 

321 

325 

213 

217 

159 

163 

127 

131 

105 

109 

91 

95 

79 

83 

1292 

GD 

1294 

321 

325 

213 

217 

159 

163 

127 

131 

105 

109 

91 

95 

79 

83 

1294 

oo 

1296 

32! 

325    I 

213 

217 

159 

163 

127 

131 

105 

109 

91 

95 

79 

83 

1296 

GD 

1298 

323 

327 

215 

219 

161 

1  65 

127 

131 

107 

111 

91 

95 

79 

83 

1298 

00 

1300 

323 

327 

215 

219 

161 

165 

127 

131 

107 

111 

91 

95 

79 

83 

1300 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute 
magnitude  of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  DOUBLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-ENTRANCY 

No.OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

en 
K 
O 

4 

POLES 

6 

POLES 

8 
POLES 

10 

POLES 

12 
POLES 

14 
POLES 

16 

POLES 

CONDUCl 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

0 
d 
T. 

CD 

1302 

323 

327 

215 

219 

161 

165 

129 

133 

107 

111 

91 

95 

79 

83 

1302 

00 

f;Yo4 

323 

327 

215 

219 

161 

165 

129 

133 

107 

111 

91 

95 

79 

83 

1301 

GD 

1306 

1    ;!25 

329 

215 

219 

161 

165 

129 

133 

107 

in 

91 

95 

79 

83 

1300 

oo 

1308 

r~:!25 

329 

215 

219 

161 

165 

129 

138 

107 

111 

!)1 

95 

79 

83 

1308 

GD 

1310 

325 

525 

217 

221 

161 

165 

129 

133 

107 

111 

91 

95 

79 

83 

1310 

oo 

1312 

325 

32!) 

217 

221 

161 

165 

12!) 

133 

107 

111 

91 

95 

79 

83 

1312 

GD 

1314 

327 

331 

217 

221 

163 

167 

129 

133 

107 

in 

91 

96 

81 

85 

1314 

00 

1316 

327 

331 

217 

221 

163 

167 

129 

133 

107 

111 

91 

95 

81   ' 

85 

1316 

GD 

1318 

327 

331 

217 

221 

163 

167 

129 

133 

107 

111 

93 

97 

81 

85 

1  3  18 

oo 

1320 

327 

331 

217 

221 

163 

167 

129 

133 

107 

111 

93 

97 

81 

85 

1320 

GD 

1322 

329 

333 

219 

223 

163 

167 

131 

135 

109 

113 

98 

97 

81 

85 

1322 

oo 

1324 

32!) 

333 

219 

223 

163 

167 

131 

135 

109 

113 

98 

97 

81 

85 

1324 

GD 

1326 

329 

333 

219 

223 

163 

167 

131 

135 

109 

113 

95 

97 

81 

85 

1320 

oo 

1328 

329 

333 

219 

223 

163 

167 

131 

135 

109 

113 

93 

97 

81 

85 

1328 

eg 

1330 

331 

335 

219 

223 

165 

169 

131 

135 

109 

113 

93 

97 

81 

85 

1330 

00 

1332 

331 

335 

219 

223 

165 

169 

131 

135 

109 

113 

93 

97 

81 

85 

1  332 

GD 

1334 

331 

335 

221 

225 

165 

169 

131 

135 

109 

113 

93 

97 

81 

85 

133-1 

oo 

1336 

331 

335 

221 

225 

165 

169 

131 

135 

109 

113 

93 

97 

81 

85 

1  336 

(2) 

1338 

333 

337 

221    i 

225 

165 

169 

131 

135 

109 

113 

93 

97 

81 

85 

1  338 

oo 

1340 

333 

337 

~2"2~1 

225 

165 

169 

131 

135 

109 

113 

93 

97 

81 

85 

1310 

GD 

1342 

333 

337 

221 

225 

165 

169 

133 

137 

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113 

93 

97 

81 

85 

1342 

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1344 

838 

337 

221 

225 

165 

169 

133 

137 

109 

113 

93 

97 

81 

85 

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GD 

1346 

335 

339 

223 

227 

167 

171 

133 

137 

111 

115 

95 

99 

83 

87 

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00 

1348 

335 

339 

223 

227 

167 

171 

133 

137 

111 

115 

'.».-> 

99 

83 

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335 

339 

223 

227 

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171 

133 

137 

111 

115 

95 

99 

83 

87 

1350 

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335 

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223 

227 

167 

171 

133 

137 

111 

115 

95 

99 

83 

87 

1352 

GD 

1354 

337 

341 

223 

227 

167 

171 

133 

137 

111 

115 

95 

99 

83 

87 

1  354 

oo 

1356 

337 

341 

223 

227 

167 

171 

133 

137 

111 

115 

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99 

83 

87 

1  356 

GD 

1358 

337 

341 

225 

229 

167 

171 

133 

137 

111 

115 

95 

99 

83 

87 

1  358 

oo 

I3<;o 

337 

341 

225 

229 

167 

171 

133 

137 

111 

115 

95 

99 

83 

87 

1360 

GD 

1362 

339 

343 

225 

229 

169 

173 

135 

139 

111 

115 

95 

99 

83 

87 

1362 

oo 

1361 

339 

343 

225 

229 

169 

173 

135 

139 

111 

115 

95 

99 

83 

87 

1364 

GD 

1366 

339 

343 

225 

229 

169 

173 

135 

139 

111 

115 

95 

99 

83 

S7 

1366 

oo 

1368 

339 

343 

225 

229 

169 

173 

135 

139 

111 

115 

95 

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83 

87 

1368 

GD 

1370 

341 

345 

227 

231 

1  69 

173 

135 

139 

113 

117 

95 

9;i 

83 

87 

1370 

oo 

1:572 

341 

345 

227 

231 

169 

173 

135 

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113 

117 

95 

99 

88 

87 

1372 

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1374 

341 

345 

227 

231 

169 

173 

135 

139 

113 

117 

97 

101 

83 

87 

1374 

oo 

1376 

:;tl 

345 

227 

231 

169 

173 

135 

139 

113 

117 

97 

101 

83 

87 

1376 

GD 

1378 

343 

347 

227 

231 

171 

175 

135 

139 

113 

117 

97 

101 

85 

89 

1378 

oo 

.1:580 

343 

347 

227 

231 

171 

175 

135 

139 

113 

117 

97 

101 

85 

so 

1381) 

CD 

1  3S2 

343 

347 

229 

233 

171 

175 

137 

141 

113 

117 

97 

101 

85 

S!> 

1  382 

oo 

1384 

343 

347 

229 

233 

171 

175 

137 

141 

113 

117 

97 

101 

85 

89 

1384 

03 

i:i8i;  • 

345 

349 

229 

233 

171 

175 

137 

141 

113 

117 

97 

101 

85 

89 

1386 

oo 

1388 

345 

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229 

233 

171 

175 

137 

141 

113 

117 

97 

101 

85 

89 

1388 

GD 

l  :t'.io 

345 

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229 

233 

171 

175 

137 

141 

113 

J17 

97 

101 

85 

89 

1390 

oo 

i:i'.»2 

345 

349 

229 

233 

171 

175 

137 

141 

113 

117 

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101 

85 

89 

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£22 

1394 

317 

351 

231 

235 

173 

177 

137 

141 

115 

119 

97 

101 

85 

89 

1394 

oo 

1396 

347 

351 

231 

2:55 

173 

177 

137 

141 

115 

119 

97 

101 

85 

89 

1396 

GD 

1398 

347 

351 

231 

235 

173 

177 

137 

141 

115 

119 

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1(11 

85 

89 

1398 

oo 

1400 

347 

351 

231 

235 

173 

177 

137 

14.1 

115 

119 

97 

101 

85 

89 

1400 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute 
magnitude  of  average  pitch  may  be  varied  within  reasonable  limits, 

MULTIPLE-CIRCUIT,  DOUBLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-ENTRANCY 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

'  CONDUCTORS 

4 

POLES 

6 

POLES 

8 
POLES 

10 

POLES 

12 

POLES 

14 

POLES 

16 
POLES 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

O 

6 

Z 

CD 

1402 

349 

353 

231 

235 

173 

177 

139 

143 

115 

119 

99 

103 

85 

89 

1402 

00 

1404 

349 

353 

231 

235 

173 

177 

188 

143 

115 

119 

99 

103 

85 

89 

1404 

C5) 

MOO 

349 

353 

233 

237 

173 

177 

139 

143 

115 

119 

99 

103 

85 

89 

1406 

00 

1408 

349 

353 

233 

237 

173 

177 

139 

143 

115 

119 

99 

103 

85 

89 

1408 

go 

1410 

_861 

355 

•2:',:', 

237 

175 

179 

139 

143 

115 

119 

99 

103 

87 

91 

1410 

00 

1412 

351 

355 

•2:i3 

237 

175 

179 

189 

143 

115 

119 

99 

103 

87 

91 

1412 

OD 

1414 

351 

355 

233 

237 

175 

179 

139 

143 

115 

119 

99 

103 

87 

91 

1414 

oo 

1416 

351 

355 

233 

2:i7 

175 

179 

139 

143 

115 

119 

99 

103 

87 

91 

1410 

CE> 

1418 

353 

357 

235 

239 

175 

179 

139 

143 

117 

121 

99 

103 

87 

91 

1418 

oo 

1420 

353 

357 

235 

239 

175 

179 

139 

143 

117 

121 

99 

103 

87 

91 

1420 

<3D 

1422 

353 

357 

23| 

239 

175 

179 

141 

145 

117 

121 

99 

103 

87 

91 

1422 

oo 

1424 

353 

357 

235 

239 

175 

179 

141 

145 

117 

121 

99 

103 

87 

91 

1424 

CE> 

1426 

355 

359 

235 

239 

177 

181 

141 

145 

117 

121 

99 

103 

87 

91 

1426 

oo 

1428 

355 

3.',!) 

235 

239 

177 

181 

141 

145 

117 

121 

99 

103 

87 

91 

1428 

C£> 

1430 

355 

359 

237 

241 

177 

181 

141 

145 

117 

121 

101 

105 

87 

91 

1480 

oo 

1432 

355 

359 

237 

241 

177 

181 

141 

145 

117 

121 

101 

105 

87 

91 

1432 

(S3 

1434 

357 

361 

237 

241 

177 

181 

141 

145 

117 

121 

101 

105 

87 

91 

1434 

00 

1436 

357 

361 

237 

241 

177 

181 

141 

145 

117 

121 

101 

105 

87 

91 

1436 

CE> 

1438 

357 

361 

237 

241 

177 

181 

141 

145 

117 

121 

101 

105 

87 

91 

1438 

oo 

1440 

357 

361 

237 

241 

177 

181 

141 

145 

117 

121 

101 

105 

87 

91 

1440 

CE> 

1442 

359 

363 

239 

243 

179 

183 

143 

147 

119 

123 

101 

105 

89 

93 

1442 

oo 

1444 

359 

363 

239 

243 

179 

183 

143 

147 

119 

123 

101 

105 

89 

93 

1444 

C£> 

1446 

359 

363 

239 

243 

179 

183 

143 

147 

119 

123 

101 

105 

89 

93 

1446 

00 

1448 

359 

363 

239 

243 

179 

183 

143 

147 

119 

123 

101 

105 

89 

93 

1448 

CO) 

1450 

361 

365 

239 

243 

179 

183 

143 

147 

119 

123 

101 

105 

89 

93 

1450 

oo 

1452 

361 

365 

239 

243 

179 

183 

143 

147 

119 

123 

101 

105 

89 

93 

1452 

O 

1454 

361 

365 

241 

245 

179 

183 

143 

147 

119 

123 

101 

105 

89 

93 

1454 

oo 

1456 

361 

305 

241 

245 

179 

183 

143 

147 

119 

123 

101 

105 

89 

93 

1456 

(33 

1458 

363 

367 

241 

245 

181 

185 

143 

147 

119 

123 

103 

107 

89 

93 

1458 

oo 

1460 

363 

367 

241 

245 

181 

185 

143 

147 

119 

123 

103 

107 

89 

93 

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® 

1402 

363 

367 

241 

245 

181 

185 

145 

149 

119 

123 

103 

107 

89 

93 

1462 

oo 

1464 

363 

367 

241 

245 

181 

185 

145 

149 

119 

123 

103 

107 

89 

93 

1464 

C53 

1466 

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369 

243 

247 

181 

185 

145 

149 

121 

125 

103 

107 

89 

93 

1466 

oo 

1468 

365 

369 

243 

247 

181 

185 

145 

149 

121 

125 

103 

107 

89 

93 

1468 

CD 

1470 

365 

369 

243 

247 

181 

185 

145 

149 

121 

125 

103 

107 

89 

93 

1470 

00 

1472 

365 

369 

243 

247 

181 

185 

145 

149 

121 

125 

103 

107 

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93 

1472 

CD 

1474 

367 

371 

243 

247 

183 

1S7 

145 

149 

121 

125 

103 

107 

91 

95 

1474 

00 

1470 

367 

371 

243 

247 

183 

187 

145 

149 

121 

125 

103 

107 

91 

95 

1476 

O> 

1478 

367 

371 

245 

249 

183 

187 

145 

149 

121 

125 

103 

107 

91 

95 

1478 

00 

14,80 

367 

371 

245 

249 

183 

187 

145 

149 

121 

125 

103 

107 

91 

95 

1480 

Cfl) 

1482 

309 

373 

245 

249 

183 

187 

147 

151 

121 

125 

103 

107 

91 

95 

1482 

oo 

1484 

369 

373 

245 

249 

183 

187 

147 

151 

121 

125 

103 

107 

91 

95 

1484 

C53 

1486 

369 

373 

•245 

249 

183 

187 

147 

151 

121 

125 

105 

109 

91 

95 

1486 

oo 

1488 

369 

373 

245 

2411 

183 

187 

147 

151 

121 

125 

105 

109 

91 

95 

1488 

Ca) 

1490 

371 

375 

247 

251 

185 

189 

117 

151 

123 

127 

105 

109 

91 

95 

1490 

oo 

1492 

371 

375 

247 

251 

185 

189 

147 

151 

123 

127 

105 

109 

91 

95 

1492 

C2) 

1494 

371 

375 

247 

251 

185 

189 

147 

151 

123 

127 

105 

109 

91 

95 

1494 

oo 

1496 

371 

375 

247 

251 

185 

189 

147 

151 

123 

127 

105 

109 

91 

95 

1496 

CE> 

1498 

373 

377 

247 

251 

185 

189 

147 

151 

12:! 

127 

105 

109 

91 

95 

1498 

00 

1500 

373 

377 

247 

251 

185 

189 

147 

151 

123 

127 

105 

109 

91 

95 

1500 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute 
magnitude  of  average  pitch  may  be  varied  within  reasonable  limits. 

or  ran 

UHIVBRSIT7 


MULTIPLE-CIRCUIT,  DOUBLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-ENTRANCY 

No.OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

CO 

cc. 
o 

4 
POLES 

6 
POLES 

8 

POLES 

10 

POLES 

12 

POLES 

14 
POLES 

16 

POLES 

CONDUC' 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

O 
o 

Z 

go 

1502 

373 

377 

249 

253 

185 

189 

149 

153 

123 

127 

105 

109 

91 

95 

1502 

00 

1504 

373 

377 

249 

253 

185 

189 

149 

153 

123 

127 

105  ' 

109 

91 

95 

1504 

go 

1506 

375 

379 

249 

253 

187 

191 

149 

153 

123 

127 

105 

109 

93 

97 

1506 

oo 

1508 

375 

379 

249 

253 

187 

191 

149 

153 

123 

127 

105 

109 

93 

97 

1508 

GD 

1510 

375 

379 

249 

253 

187 

191 

149 

153 

123 

127 

105 

109 

93 

97 

1510 

oo 

1512 

375 

379 

249 

253 

187 

191 

149 

153 

123 

127 

105 

109 

93 

97 

1512 

GD 

1514 

377 

381 

251 

255 

187 

191 

149 

153 

125 

129 

107 

111 

93 

97 

1514 

oo 

1516 

377 

381 

251 

255 

187 

191 

149 

153 

125 

129 

107 

111 

93 

97 

1516 

GD 

1518 

377 

381 

251 

255 

187 

191 

149 

153 

125 

129 

107 

111 

93 

97 

lf>  IS 

00 

1520 

377 

381 

251 

255 

187 

191 

149 

153 

125 

129 

107 

111 

93 

97 

1520 

35 

1522 

379 

383 

251 

255 

189 

193 

151 

155 

125 

129 

107 

111 

93 

97 

1522 

oo 

1524 

1579 

383 

251 

255 

189 

193 

151 

155 

125 

129 

107 

111 

93 

97 

1524 

05 

1  :,26 

379 

383 

253 

257 

189 

193 

151 

155 

125 

129 

107 

111 

93 

97 

1526 

oo 

1528 

379 

383 

253 

257 

189 

193 

151 

155 

125 

129 

107 

111 

93 

97 

1628 

GD 

1530 

381 

385 

253 

257 

189 

193 

151 

155 

125 

129 

107 

111 

93 

97 

1530 

oo 

1532 

381 

385 

253 

•2:,  - 

189 

193 

151 

155 

125 

129 

107 

111 

93 

97 

1532 

GD 

1534 

381 

385 

253 

•257 

189 

193 

151 

155 

125 

129 

107 

111 

93 

97 

1534 

oo 

15:56 

;>,si 

385 

253 

257 

ls:i 

193 

151 

155 

125 

129 

107 

111 

93 

97 

1536 

GO 

1538 

:;s;>, 

:;s, 

255 

259 

191 

195 

151 

155 

127 

131 

107 

111 

95 

99 

1538 

oo 

1540 

383 

3S7 

255 

259 

191 

195 

151 

155 

127 

131 

107 

111 

95 

99 

1540 

GD 

1542 

383 

387 

255 

259 

191 

195 

153 

157 

127 

131 

109 

113 

95 

99 

1  542 

00 

1544 

383 

387 

255 

259 

191 

195 

153 

157 

127 

131 

109 

113 

95 

99 

1544 

GD 

1546 

3S5 

389 

255 

259 

191 

195 

153 

157 

127 

131 

109 

113 

95 

99 

1  546 

oo 

1548 

385 

389 

255 

259 

191 

195 

153 

157 

127 

131 

109 

113 

95 

99 

1548 

GD 

1550 

385 

389 

257 

261 

191 

195 

153 

157 

127 

131 

ID'.) 

113 

95 

99 

1550 

oo 

1552 

385 

389 

257 

261 

191 

195 

153 

157 

127 

131 

109 

113 

95 

99 

1552 

CD 

1554 

387 

391 

257 

261 

193 

197 

153 

157 

127 

131 

109 

113 

95 

99 

1554 

oo 

1556 

3H7 

391 

257 

261 

193 

197 

153 

157 

127 

131 

109 

113 

95 

99 

1556 

GD 

]558 

387 

391 

257 

261 

193 

197 

153 

157 

127 

131 

109 

113 

95 

99 

1558 

oo 

1560 

387 

391 

257 

261 

193 

197 

153 

157 

127 

131 

109 

113 

95 

99 

1560 

GD 

1562 

389 

393 

259 

263 

193 

197 

155 

159 

129 

133 

109 

113 

95 

99 

1562 

oo 

1564 

389 

393 

259 

263 

193 

197 

155 

159 

129 

133 

109 

113 

95 

99 

1564 

GD 

1566 

389 

393 

259 

263 

193 

197 

155 

159 

129 

133 

109 

113 

95 

99 

1566 

oo 

1568 

389 

393 

259 

263 

193 

197 

155 

159 

129 

133 

109 

113 

95 

99 

1568 

GD 

1570 

391 

395 

259 

263 

195 

199 

155 

159 

129 

138 

111 

115 

97 

101 

1570 

00 

1572 

391 

395 

259 

263 

195 

199 

155 

159 

129 

133 

111 

115 

97 

101 

1572 

GD 

1  57  1 

391 

395 

261 

265 

195 

199 

155 

159 

129 

133 

111 

115 

97 

101 

1574 

oo 

1576 

391 

395 

261 

265 

195 

199 

155 

159 

129 

133 

111 

115 

97 

101 

1576 

GD 

1.5  7S 

393 

397 

261 

265 

195 

199 

155 

159 

129 

133 

111 

115 

97 

101 

157S 

oo 

1580 

393 

397 

261 

265 

195 

199 

155 

159 

129 

133 

111 

115  1 

97 

101 

1580 

GD 

15H2 

393 

397 

261 

265 

195 

199 

157 

161 

129 

133 

111 

115 

97 

101 

1582 

00 

1584 

393 

397 

261 

265 

195 

199 

157 

161 

129 

133 

111 

115 

97 

101 

1584 

GD 

i:>si; 

395 

399 

263 

267 

197 

201 

157 

161 

131 

135 

111 

115 

97 

101 

1586 

00 

1588 

395 

399 

263 

267 

197 

201 

157 

161 

131 

135 

111 

115 

97 

101 

1588 

GD 

1590 

395 

:',',)'.! 

263 

267 

197 

201 

157 

161 

131 

135 

111 

115 

97 

101 

1590 

oo 

1592  i 

395 

399 

263 

267 

197 

201 

157 

161 

131 

135 

111 

115 

97 

101 

1592 

GD 

1594 

397 

401 

263 

267 

197 

201 

157 

161 

131 

135 

111 

115 

97 

101 

1594 

oo 

1596 

397 

401 

263 

267 

197 

201 

157 

161 

131 

135 

111 

115 

97 

101 

15% 

GD 

J.V.IS 

397 

mi 

265 

269 

197 

201 

157 

161 

131 

135 

113 

117 

97 

101 

1598 

oo 

1600 

397 

401 

265 

269 

197 

201 

157 

161 

131 

135 

113 

117 

97 

101 

1600 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute 
magnitude  of  average  pitch  may  be  varied  within,  reasonable  limits. 

WINDING   TABLES   FOR   MULTIPLE-CIRCUIT,  TRIPLE   WINDINGS 

FOR  DRUM   ARMATURES. 


MULTIPLE-CIRCUIT,  TRIPLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-ENTRANCY 

No.OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

No.OF  CONDUCTORS 

4 
POLES 

6 
POLES 

8 

POLES 

10 
POLES 

12 

POLES 

14 
POLES 

16 

POLES 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

<s> 

202 

47 

53 

31 

37 

23 

29 

17 

23 

13 

19 

11 

17 

9 

15 

202 

ooo 

•204 

47 

53 

31 

37 

23 

29 

17 

23 

13 

19 

11 

17 

9 

15 

204 

m 

206 

49 

55 

31 

37 

23 

29 

17 

23 

15 

21 

11 

17 

9 

15 

206 

8$) 

203 

•19 

55 

31 

37 

23 

29 

17 

23 

15 

21 

11 

17 

9 

15 

208 

000 

210 

49 

55 

31 

37 

23 

29 

17 

23 

15 

21 

11 

17 

11 

17 

210 

m 

212 

49 

55 

33 

39 

23 

29 

19 

25 

15 

21 

13 

19 

11 

17 

212 

(as) 

214 

51 

57 

33 

39 

23 

29 

19 

25 

15 

21 

13 

19 

11 

17 

214 

ooo 

216 

51 

57 

33 

39 

23 

29 

19 

25 

15 

21 

13 

19 

11 

17 

216 

(aa) 

218 

51 

57 

33 

39 

25 

31 

19 

25 

15 

21 

13 

19 

11 

17 

218 

(as) 

220 

51 

57 

33 

39 

125 

31 

19 

25 

15 

21 

13 

19 

11 

17 

220 

ooo 

222 

63 

59 

33 

39 

25 

31 

19 

25 

15 

21 

13 

19 

11 

17 

222 

(5s) 

224 

53 

59 

35 

41 

25 

31 

19 

25 

15 

21 

13 

19 

11 

17 

224 

(22) 

226 

53 

59 

35 

41 

25 

31 

19 

25 

15 

21 

13 

19 

11 

17 

226 

ooo 

228 

53 

59 

35 

41 

25 

31 

19 

25 

15 

21 

13 

19 

11 

17 

228 

Gfi) 

230 

55 

61 

35 

41 

25 

31 

19 

25 

17 

2:5 

13 

19 

11 

17 

230 

55 

232 

55 

61 

35 

41 

25 

31 

21 

27 

17 

23 

13 

19 

11 

17 

232 

ooo 

•2:u 

55 

61 

35 

41 

27 

33 

21 

27 

17 

23 

13 

19 

11 

17 

234 

(52) 

236 

55 

61 

37 

43 

27 

33 

21 

27 

17 

23 

13 

19 

11 

17 

236 

(ca) 

238 

57 

63 

37 

43 

27 

;!:>, 

21 

27 

17 

23 

13 

19 

11 

17 

238 

ooo 

240 

57 

63 

37 

43 

27 

33 

21 

27 

17 

23 

15 

21 

11 

17 

240 

®> 

242 

57 

03 

37 

43 

27 

33 

21 

27 

17 

23 

15 

21 

13 

19 

242 

(S) 

244 

57 

63 

37 

43 

27 

33 

21 

27 

17 

23 

15 

21 

13 

19 

244 

000 

246 

59 

65 

37 

43 

27 

33 

21 

27 

17 

28 

15 

21 

13 

19 

246 

(55) 

248 

59 

65 

39 

45 

27 

n 

21 

27 

17 

23 

15 

21 

13 

19 

248 

35 

250 

59 

65 

I     39 

45 

29 

35 

21 

27 

17 

23 

15 

21 

13 

19 

250 

ooo 

252 

59 

65 

39 

45 

29 

35 

23 

29 

17 

23 

15 

21 

13 

19 

252 

(Sa) 

254 

61 

67 

39 

45 

29 

35 

23 

29 

19 

25 

15 

21 

13 

19 

254 

<Sa) 

256 

61 

67 

39 

45 

29 

35 

23 

29 

19 

25 

15 

21 

13 

19 

256 

ooo 

258 

01 

67 

39 

45 

29 

35 

23 

29 

19 

25 

15 

21 

13 

19 

258 

(aa) 

260 

61 

67 

41 

47 

29 

35 

23 

29 

19 

25 

15 

21 

13 

19 

260 

(5a) 

262 

63 

69 

41 

47 

29 

35 

23 

29 

19 

25 

15 

21 

13 

19 

262 

000 

264 

63 

69 

41 

47 

29 

35 

23 

29 

19 

25 

15 

21 

13 

19 

264 

(as) 

266 

03 

69 

41 

47 

31 

37 

23 

29 

19 

25 

15 

21 

13 

19 

266 

(as) 

208 

63 

69 

41 

47 

31 

37 

23 

29 

19 

25 

17 

23 

13 

19 

268 

000 

270 

65 

71 

41 

47 

31 

37 

23 

29 

19 

25 

17 

23 

13 

19 

270 

(Sa) 

272 

65 

71 

43 

49 

31 

37 

25 

111 

19 

25 

17 

23 

13 

19 

272 

(Ca) 

274 

65 

71 

48 

49 

31 

37 

25 

31 

19 

25 

17 

23 

15 

21 

274 

ooo 

276 

65 

71 

4:', 

49 

31 

37 

25 

31 

19 

25 

17 

23 

15 

21 

276 

(aa) 

278 

07 

73 

43 

49 

31 

37 

25 

31 

21 

27 

17 

23 

15 

21 

278 

555 

280 

67 

73 

43 

49 

31 

37 

25 

31 

21 

27 

17 

23 

15 

21 

280 

ooo 

282 

67 

73 

43 

49 

33 

39 

25 

31 

21 

27 

17 

23 

15 

21 

282 

55T 

284 

67 

73 

45 

51 

33 

39 

•25 

31 

21 

27 

17 

23 

15 

21 

284 

(aa) 

286 

69 

75 

45 

51 

33 

39 

25 

31 

21 

27 

17 

23 

15 

21 

286 

000 

288 

69 

75 

45 

51 

33 

39 

25 

31 

21 

27 

17 

23 

15 

21 

288 

(aa) 

290 

69 

75 

45 

51 

33 

39 

25 

31 

21 

27 

17 

23 

15 

21 

290 

(sa) 

292 

69 

75 

45 

51 

33 

39 

27 

33 

21 

27 

17 

23 

15 

21 

292 

ooo 

294 

71 

77 

46 

51 

33 

39 

27 

33 

21 

27 

17 

23 

15 

21 

294 

(aa) 

296 

71 

77 

47 

53 

33 

39 

27 

33 

21 

27 

19 

25 

15 

21 

296 

(aa) 

298 

71 

77 

47 

53 

86 

41 

27 

33 

21 

27 

19 

25 

15 

21 

298 

ooo 

300 

71 

77 

47 

53 

35 

41 

27 

33 

21 

27 

19 

25 

15 

21 

300 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute 
magnitude  of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  TRIPLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-EVTOANCY 

No.OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

CO 

o: 
o 

4 

POLES 

6 

POLES 

8 

POLES 

10 
POLES 

12 
POLES 

14 
POLES 

16 

POLES 

CONDUC" 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

0 

6 

Z 

(22) 

302 

73 

79 

47 

53 

35 

41 

27 

33 

23 

29 

19 

25 

15 

21 

302 

(SB) 

304 

73 

79 

47 

53 

35 

41 

27 

33 

23 

29 

19 

25 

15 

21 

304 

000 

300 

73 

79 

47 

53 

35 

41 

27 

33 

23 

29 

19 

25 

17 

23 

306 

(ss) 

308 

73 

79 

49 

55 

35 

41 

27 

33 

23 

29 

19 

25 

17 

23 

308 

(as) 

310 

75 

81 

49 

55 

35 

41 

27 

33 

23 

29 

19 

25 

17 

28 

310 

ooo 

312 

75 

81 

49 

55 

35 

41 

29 

35 

23 

29 

19 

25 

17 

23 

312 

(22) 

314 

75 

81 

49 

55 

37 

43 

29 

35 

23 

29 

19 

26 

17 

23 

314 

(22) 

316 

75 

81 

49 

55 

37 

43 

29 

35 

23 

29 

19 

25 

17 

23 

316 

000 

318 

77 

83 

49 

55 

37 

43 

29 

35 

23 

29 

19 

25 

17 

23 

318 

aw 

320 

77 

83 

51 

57 

37 

43 

29 

35 

23 

29 

19 

25 

17 

28 

320 

(§a) 

322 

77 

83 

51 

57 

37 

43 

29 

35 

23 

29 

19 

25 

17 

23 

322 

ooo 

324 

77 

83 

51 

57 

37 

43 

29 

35 

23 

29 

21 

27 

17 

23 

324 

(22) 

326 

79 

85 

51 

57 

37 

43 

29 

35 

25 

31 

21 

27 

17 

23 

326 

(52) 

328 

71) 

85 

51 

57 

37 

43 

29 

35 

25 

31 

21 

27 

17 

23 

328 

000 

330 

79 

85 

51 

57 

39 

45 

29 

35 

25 

31 

21 

27 

17 

23 

330 

(22) 

332 

79 

85 

53 

59 

39 

45 

31 

37 

25 

31 

21 

27 

17 

23 

1332 

(22) 

334 

81 

87 

53 

59 

39 

45 

31 

37 

25 

31 

21 

27 

17 

23 

334 

ooo 

336 

81 

87 

53 

59 

39 

45 

31 

37 

25 

31 

21 

27 

17 

23 

330 

(52) 

338 

81 

87 

53 

59 

39 

45 

31 

37 

25 

31 

21 

27 

19 

25 

338 

(82) 

340 

81 

87 

53 

59 

39 

45 

31 

37 

25 

31 

21 

27 

19 

26 

340 

ooo 

342 

S3 

89 

53 

59 

39 

45 

31 

37 

25 

31 

21 

27 

19 

25 

342 

(22) 

344 

83 

89 

55 

61 

39 

45 

31 

37 

25 

31 

21 

27 

19 

25 

344 

(5s) 

346 

83 

89 

55 

61 

41 

47 

31 

37 

25 

31 

21 

27 

19 

25 

310 

000 

348 

83 

89 

55 

61 

41 

47 

31 

37 

25 

31 

21 

27 

19 

25 

348 

(22) 

350 

85 

91 

55 

61 

41 

47 

31 

37 

27 

33 

21 

27 

19 

25 

350 

(22) 

352 

85 

91 

55 

61 

41 

47 

33 

89 

27 

33 

23 

29 

19 

25 

352 

ooo 

354 

85 

91 

55 

61 

41 

47 

33 

39 

27 

33 

23 

29 

19 

25 

354 

(22) 

356 

85 

91 

57 

63 

41 

47 

33 

39 

27 

33 

23 

29 

19 

25 

350 

(8$) 

358 

87 

93 

57 

63 

41 

47 

33 

39 

27 

33 

23 

29 

19 

25 

35S 

000 

360 

87 

93 

b'l 

63 

41 

47 

33 

39 

27 

33 

23 

29 

19 

25 

360 

(55) 

362 

87 

93 

57 

63 

43 

49 

33 

39 

27 

33 

23 

29 

19 

25 

362 

(52) 

364 

87 

93 

57 

63 

43 

49 

33 

39 

27 

33 

23 

29 

19 

25 

364 

ooo 

300 

89 

95 

57 

63 

43 

49 

33 

39 

27 

33 

23 

29 

19 

25 

366 

(22) 

368 

89 

95 

59 

65 

43 

49 

33 

39 

27 

33 

23 

29 

19 

25 

368 

(22) 

370 

89 

95 

59 

65 

43 

49 

33 

39 

27 

33 

23 

29 

21 

27 

370 

ooo 

372 

89 

95 

59 

65 

43 

49 

35 

41 

27 

33 

23 

29 

21 

27 

372 

(22) 

374 

91 

97 

59 

65 

43 

49 

35 

41 

29 

35 

23 

29 

21 

27 

374 

_.(22). 

376 

91 

97 

59 

65 

43 

49 

35 

41 

29 

86 

23 

29 

21 

27 

376 

000 

378 

91 

97 

59 

65 

45 

51 

35 

41 

28 

35 

23 

29 

21 

27 

378 

(52) 

380 

91 

97 

61 

67 

45 

51 

35 

41 

29 

35 

25 

31 

21 

27 

380 

(22) 

382 

93 

99 

61 

67 

45 

51 

35 

41 

29 

35 

.    25 

31 

21 

27 

382 

ooo 

384 

93 

99 

61 

67 

45 

51 

35 

41 

29 

35 

25 

31 

21 

27 

381 

(22) 

386 

93 

99 

61 

67 

45 

51 

35 

41 

29 

35 

25 

31 

21 

27 

386 

(22) 

8_g§ 

93 

99 

61 

67 

45 

51 

35 

41 

29 

35 

25 

31 

21 

27 

38S 

ooo 

390 

95 

101 

61 

67 

45 

51 

35 

41 

29 

35 

25 

31 

21 

27 

390 

(28) 

392 

95 

101 

63 

69 

45 

51 

37 

43 

29 

35 

26 

31 

21 

27 

392 

(S) 

394 

95 

101 

63 

69 

47 

53 

37 

43 

29 

35 

25 

31 

21 

27 

394 

ooo 

396 

95 

101 

63 

69 

47 

53 

37 

43 

29 

35 

25 

31 

21 

27 

396 

(22) 

398 

97 

103 

63 

69 

47 

53 

37 

43 

31 

37 

25 

31 

21 

27 

398 

;  (2s) 

400 

97 

103 

63          69 

47 

53 

37 

13 

31 

37 

25 

31 

21 

27 

400 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute 
magnitude  of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT   TRIPLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-ENTRANCY 

NO.OFCONDUCTORS 

FRONT  AND  BACK  PITCHES 

No.  OF  CONDUCTORS 

4 

POLES 

6 

POLES 

8 
POLES 

10 

POLES 

12 

POLES 

14 
POLES 

16 

POLES 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

ooo 

402 

97 

103 

63 

09 

47 

53 

37 

43 

31 

37 

25 

31 

23 

29 

402 

(5$) 

404 

97 

103 

65 

71 

47 

53 

37 

48 

31 

37 

25 

31 

23 

29 

404 

@> 

400 

99 

105 

65 

71 

47 

53 

37 

43 

31 

37 

25 

31 

23 

29 

406 

ooo 

408 

99 

105 

65 

71 

47 

5§ 

37 

43 

31 

37 

27 

33 

23 

29 

408 

<SS) 

410 

99 

105 

65 

71 

49 

55 

37 

43 

31 

37 

27 

33 

23 

29 

410 

CSD 

412 

99 

105 

65 

71 

49 

55 

39 

45 

31 

37 

27 

33 

23 

29 

412 

ooo 

414 

101 

107 

65 

71 

49 

55 

39 

45 

31 

37 

27 

33 

23 

29 

414 

m 

416 

101 

107 

67 

73 

49 

55 

39 

45 

81 

37 

27 

33 

23 

29 

416 

(53) 

418 

101 

107 

67 

73 

49 

65 

39 

45 

31 

37 

27 

33 

23 

29 

418 

ooo 

420 

101 

107 

67 

73 

49 

55 

39 

45 

31 

37 

27 

33 

23 

29 

420 

(Ss) 

422 

103 

109 

67 

7i! 

49 

55 

39 

45 

33 

39 

27 

33 

23 

29 

422 

(8S) 

424 

103 

109 

07 

73 

49 

55 

39 

45 

33 

39 

27 

33 

23 

29 

424 

ooo 

426 

103 

109 

67 

73 

51 

57 

39 

45 

33 

39 

27 

33 

23 

29 

426 

(52) 

428 

103 

109 

69 

75 

51 

57 

39 

45 

33 

39 

27 

33 

23 

2<J 

428 

(M) 

430 

105 

111 

69 

75 

51 

57 

39 

45 

33 

39 

27 

33 

23 

29 

430 

ooo 

432 

105 

111 

69 

75 

51 

57 

41 

47 

33 

39 

27 

33 

23 

29 

432 

@) 

434 

105 

111 

69 

75 

51 

57 

41 

47 

33 

39 

27 

33 

25 

31 

434 

®) 

436 

105 

111 

69 

75 

51 

57 

41 

47 

33 

39 

29 

35 

25 

31 

436 

ooo 

438 

107 

113 

69 

75 

51 

57 

41 

47 

33 

39 

29 

35 

25 

31 

438 

(SSL. 

440 

107 

113 

71 

77 

51 

57 

41 

47 

33 

39 

29 

35 

25 

31 

440 

(SS) 

442 

107 

113 

71 

77 

53 

59 

41 

47 

33 

39 

29 

35 

25 

31 

442 

ooo 

444 

107 

113 

71 

77 

53 

59 

41 

47 

33 

39 

29 

35 

25 

31 

444 

(5s) 

446 

109 

115 

71 

77 

53 

5!! 

41 

47 

35 

41 

29 

35 

25 

31 

446 

£2D 

448 

109 

115 

71 

77 

n 

68 

41 

47 

35 

41 

29 

35 

25 

31 

448 

ooo 

450 

109 

115 

71 

77 

53 

69 

41 

47 

35 

41 

29 

35 

25 

31 

450 

(22) 

452 

109 

115 

73 

79 

53 

69 

43 

49 

35 

41 

29 

35 

25 

31 

452 

(3) 

454 

111 

117 

78 

79 

53 

59 

43 

49 

35 

41 

29 

35 

25 

31 

454 

ooo 

456 

ill 

117 

78 

79 

53 

59 

43 

49 

35 

41 

29 

35 

25 

31 

456 

(55} 

458 

111 

117 

73 

79 

55 

61 

43 

49 

35 

41 

29 

35 

25 

31 

458 

(5?) 

460 

111 

117 

73 

79 

55 

61 

43 

49 

35 

41 

29 

35 

25 

31 

460 

ooo 

462 

113 

119 

73 

79 

55 

61 

43 

49 

35 

41 

29 

35 

25 

31 

462 

<S) 

464 

113 

119 

75 

81 

55 

(11 

43 

49 

35 

41 

31 

37 

25 

31 

464 

{S3 

466 

113 

119 

75 

81 

55 

61 

43 

49 

35 

41 

31 

37 

27 

33 

466 

ooo 

468 

113 

119 

75 

81 

55 

61 

43 

49 

35 

41 

31 

37 

27 

33 

468 

63) 

470 

116 

121 

75 

81 

55 

61 

43 

49 

37 

43 

31 

37 

27 

33 

470 

(55) 

472 

115 

121 

75 

81 

55 

61 

45 

51 

37 

43 

31 

37 

27 

33 

472. 

ooo 

474 

115 

121 

75 

81 

57 

63 

45 

51 

37 

43 

31 

37 

27 

33 

474 

_M)_ 

476 

115 

121 

77 

83 

57 

68 

45 

51 

37 

43 

31 

37 

27 

33 

476 

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478 

117 

123 

77 

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57 

63 

45 

51 

37 

43 

31 

37 

27 

33 

478 

000 

480 

117 

123 

77 

83 

57 

63 

45 

51 

37 

43 

31 

37 

27 

33 

480 

(SB) 

482 

117 

123 

77 

83 

57 

63 

45 

51 

37 

43 

31 

37 

27 

33 

482 

22) 

484 

117 

123 

77 

83 

57 

63 

45 

61 

37 

43 

31 

37 

27 

33 

484 

ooo 

486 

119 

125 

77 

83 

57 

63 

45 

51 

37 

43 

31 

37 

27 

33 

486 

<5a> 

488 

119 

125 

79 

85 

57 

63 

45 

51 

37 

43 

31 

37 

27 

33 

488 

©> 

490 

119 

125 

79 

85 

59 

65 

45 

51 

37 

43 

31 

37 

27 

33 

490 

ooo 

492 

119 

125 

79 

85 

59 

65 

47 

53 

37 

43 

33 

39 

27 

33 

492 

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494 

121 

127 

79 

85 

59 

65 

47 

53 

39 

45 

33 

39 

27 

33 

494 

(55) 

496 

121 

127 

79 

85 

59 

65 

47 

53 

39 

45 

33 

39 

27 

33 

496 

000 

498 

121 

127 

79 

S5 

59 

65 

47 

53 

39 

45 

33 

39 

29 

35 

41)8 

OS) 

500 

121 

127 

81 

87 

59 

65 

47 

53 

39 

45 

33 

39 

29 

35 

500 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute 
magnitude  of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  TRIPLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-ENTRANCY 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

No.  OF  CONDUCTORS 

4 

POLES 

6 

POLES 

8 
POLES 

10 
POLES 

12 

POLES 

14 
POLES 

16 

POLES 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

(as) 

502 

123 

129 

81 

87 

59 

65 

47 

53 

3'.t 

45 

33 

39 

29 

35 

502 

ooo 

504 

123 

12',) 

81 

87 

59 

65 

47 

53 

39 

45 

33 

39 

29 

35 

504 

(2ft) 

506 

123 

129 

81 

S7 

61 

67 

47 

53 

39 

45 

33 

39 

29 

35 

506 

($$) 

508 

123 

129 

81 

87 

61 

67 

47 

53 

39 

45 

33 

89 

2'.) 

35 

508 

000 

510 

125 

131 

M 

87 

61 

67 

47 

53 

39 

45 

33 

39 

29 

35 

510 

512 

125 

131 

83 

89 

61 

67 

49 

55 

39 

45 

33 

39 

29 

35 

512 

514 

125 

131 

83 

89 

61 

67 

49 

55 

39 

45 

33 

89 

29 

35 

514 

000 

516 

125 

131 

83 

89 

61 

67 

49 

55 

39 

45 

33 

39 

29 

35 

516 

(as) 

518 

127 

133 

83 

89 

61 

67 

49 

55 

41 

47 

88 

39 

29 

35 

518 

(55) 

520 

127 

133 

83 

89 

61 

67 

49 

55 

41 

47 

35 

41 

29 

35 

520 

ooo 

522 

127 

133 

83 

89 

63 

69 

49 

55 

41 

47 

35 

41 

29 

35 

522 

(§ft) 

524 

127 

133 

85 

91 

63 

69 

49 

55 

41 

47 

35 

41 

29 

35 

52  1 

m 

526 

12!) 

135 

85 

91 

58 

69 

49 

55 

41 

47 

35 

41 

29 

35 

526 

000 

528 

129 

135 

85 

91 

63 

69 

49 

55 

41 

47 

35 

41 

29 

35 

528 

(2ft) 

530 

129 

135 

85 

91 

63 

69 

49 

55 

41 

47 

35 

41 

31 

37 

530 

(as) 

532 

129 

135 

85 

91 

63 

69 

•51 

57 

41 

47 

35 

41 

31 

37 

532 

ooo 

534 

131 

137 

85 

91 

63 

69 

51 

57 

41 

47 

35 

41 

31 

37 

534 

(2ft) 

536 

131 

137 

87 

93 

63 

69 

51 

57 

41 

47 

35 

41 

31 

37 

536 

(2ft) 

538 

131 

137 

87 

93 

65 

71 

51 

57 

41 

47 

35 

41 

31 

37 

53  H 

000 

540 

131 

137 

87 

93 

65 

71 

51 

57 

41 

47 

35 

41 

31 

37 

540 

(2ft) 

542 

133 

139 

87 

93 

65 

71 

51 

57 

43 

49 

35 

41 

31 

37 

542 

(2ft) 

544 

133 

139 

87 

93 

65 

71 

51 

57 

43 

49 

35 

41 

31 

37 

544 

ooo 

546 

133 

139 

87 

93 

65 

71 

51 

57 

43 

49 

35 

41 

31 

37 

546 

_<S£_ 

548 

133 

139 

89 

95 

65 

71 

51 

57 

43 

49 

37 

43 

31 

37 

548 

<3fl) 

550 

135 

111 

89 

95 

65 

71 

51 

57 

43 

49 

37 

43 

31 

37 

550 

ooo 

552 

135 

141 

89 

95 

65 

71 

53 

59 

43 

49 

37 

13 

31 

37 

552 

(2ft) 

554 

186 

141 

89 

95 

67 

73 

53 

59 

43 

49 

37 

43 

31 

37 

554 

(28) 

556 

135 

141 

89 

95 

67 

73 

53 

59 

43 

49 

37 

43 

31 

37 

556 

000 

558 

137 

143 

89 

95 

67 

73 

53 

59 

43 

49 

37 

43 

31 

37 

558 

(5D 

560 

137 

143 

91 

97 

67 

73 

53 

59 

43 

49 

37 

43 

31 

37 

560 

(2ft) 

562 

137 

113 

91 

97 

67 

73 

53 

59 

43 

49 

37 

43 

33 

39 

562 

ooo 

564 

137 

143 

91 

97 

67 

73 

53 

59 

43 

49 

37 

43 

33 

39 

5li4 

55 

5(>6 

139 

145 

91 

97 

67 

73 

53 

59 

45 

51 

37 

43 

33 

39 

5Ji6 

(2ft) 

568 

139 

145 

91 

97 

67 

73 

53 

59 

45 

51 

37 

43 

33 

39 

568 

ooo 

570 

139 

145 

91 

97 

69 

75 

53 

59 

45 

51 

37 

43 

33 

39 

570 

as) 

572 

139 

145 

93 

99 

69 

75 

55 

61 

45 

51 

37 

43 

33 

39 

572 

<15) 

574 

141 

147 

93 

99 

69 

75 

55 

61 

45 

51 

37 

43 

33 

39 

574 

ooo 

57(1 

141 

147 

93 

99 

69 

75 

55 

61 

45 

51 

3!) 

45 

33 

39 

576 

(2ft) 

578 

141 

11, 

93 

99 

69 

75 

55 

61 

45 

51 

39 

45 

33 

39 

578 

(2fl) 

580 

141 

147 

93 

99 

69 

75 

55 

61 

45 

51 

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45 

33 

39 

580 

ooo 

582 

143 

149 

93 

99 

69 

75 

56 

61 

45 

51 

39 

45 

33 

39 

582 

(2ft) 

584 

113 

149 

95 

101 

69 

75 

55 

61 

45 

51 

39 

45 

33 

39 

584 

28 

586 

143 

149 

95 

101 

71 

77 

55 

61 

45 

51 

39 

45 

33 

39 

586 

000 

588 

113 

149 

95 

101 

71 

77 

55 

61 

45 

51 

39 

45 

33 

39 

588 

(2fi) 

590 

145 

151 

95 

101 

71 

77 

55 

(11 

47 

53 

39 

45 

33 

39 

590 

®> 

592 

145 

151 

95 

101 

71 

77 

57 

63 

47 

53 

39 

45 

33 

39 

592 

ooo 

594 

145 

151 

95 

101 

71 

77 

57 

63 

47 

53 

39 

45 

35 

41 

594 

(2ft) 

596 

115 

151 

97 

103 

71 

77 

57 

63 

47 

68 

39 

45 

35 

41 

596 

(2ft) 

598 

147 

153 

97 

103 

VI 

77 

57 

63 

47 

53 

39 

45 

35 

41 

598 

000 

600 

147 

153 

'.)7 

103 

71 

77 

57 

63 

47 

53 

39 

45 

35 

41 

600 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute 
magnitude  of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  TRIPLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-ENTRANCY 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

CO 

K 
o 

4 

POLES 

6 

POLES 

8 
POLES 

10 

POLES 

12 

POLES 

14 

POLES 

16 

POLES 

CON  DUG' 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

o 

d 

Z 

(SS) 

002 

147 

153 

97 

103 

73 

79 

57 

63 

47 

53 

39 

45 

35 

41 

602 

(aa) 

604 

147 

153 

97 

103 

73 

79 

57 

63 

47 

53 

41 

47 

35 

41 

604 

ooo 

006 

149 

155 

97 

103 

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57 

63 

47 

53 

41 

47 

35 

41 

606 

SB) 

008 

149 

155 

99 

105 

73 

79 

57 

63 

47 

53 

41 

47 

35 

41 

608 

(§5) 

610 

149 

155 

99 

105 

73 

79 

57 

63 

47 

53 

41 

47 

35 

41 

610 

ooo 

612 

_  149 

155 

99 

105 

73 

79 

59 

65 

47 

53 

41 

47 

35 

41 

012 

<S2 

614 

151 

157 

99 

105 

73 

79 

59 

65 

49 

55 

41 

47 

35 

41 

614 

(52) 

616 

151 

157 

99 

105 

73 

79 

59 

65 

49 

55 

41 

47 

35 

41 

616 

000 

618 

151 

157 

99 

105 

75 

81 

59 

65 

49 

55 

41 

47 

35 

41 

618 

(55) 

020 

151 

157 

101 

107 

75 

81 

59 

65 

49 

55 

41 

47 

35 

41 

620 

<3a) 

622 

153 

159 

101 

107 

75 

81 

59 

65 

49 

55 

41 

47 

35 

41 

622 

000 

624 

153 

159 

101 

107 

75 

81 

59 

65 

49 

55 

41 

47 

35 

41 

624 

(2ft) 

626 

153 

159 

101 

107 

75 

81 

59 

65 

49 

55 

41 

47 

37 

43 

626 

(55) 

028 

153 

159 

101 

107 

75 

81 

59 

65 

49 

55 

41 

47 

37 

43 

628 

000 

630 

155 

161 

101 

107 

75 

81 

59 

65 

49 

55 

41 

47 

37 

43 

630 

(25) 

632 

155 

161 

103 

109 

75 

81 

01 

67 

49 

55 

43 

49 

37 

43 

632 

(55) 

634 

155 

101 

103 

109 

77 

83 

01 

67 

49 

55 

43 

49 

37 

43 

634 

ooo 

630 

155 

161 

103 

109 

77 

83 

Gl 

67 

49 

55 

43 

49 

37 

43 

636 

CM) 

038 

157 

163 

103 

109 

77 

83 

61 

67 

51 

57 

43 

49 

37 

43 

638 

(£2) 

040 

157 

163 

103 

109 

77 

83 

61 

67 

51 

57 

43 

49 

37 

43 

640 

ooo 

642 

157 

163 

103 

109 

77 

83 

61 

67 

51 

57 

43 

49 

37 

43 

642 

(55) 

044 

157 

103 

105 

111 

77 

83 

61 

67 

51 

57 

43 

49 

37 

43 

644 

(55) 

646 

159 

105 

105 

111 

77 

83 

61 

67 

51 

57 

43 

49 

37 

43 

646 

000 

648 

159 

165~ 

105 

111 

77 

83 

01 

07 

51 

57 

43 

49 

37 

43 

648 

(ea) 

650 

159 

1  65    1 

105 

111 

79 

85 

61 

67 

51 

57 

43 

49 

37 

43 

650 

(as) 

652 

159 

105 

105 

111 

79 

85 

63 

69 

51 

57 

43 

49 

37 

43 

652 

ooo 

654 

161 

167 

105 

111 

79 

85 

63 

09 

51 

57 

43 

49 

37 

43 

654 

(28) 

656 

161 

167 

107 

113 

79 

85 

63 

09 

51 

57 

43 

49 

37 

43 

656 

(as) 

658 

161 

167 

107 

113 

79 

85 

63 

69 

51 

57 

43 

49 

39 

45 

658 

ooo 

660 

161 

167 

107 

113 

79 

85 

63 

69 

51 

57 

45 

51 

39 

45 

660 

(55) 

662 

163 

109 

107 

113 

79 

85 

63 

69 

53 

59 

45 

51 

39 

45 

662 

®) 

664 

163 

169 

107 

113 

79 

85 

03 

69 

53 

59 

45 

51 

39 

45 

664 

ooo 

666 

163 

169 

107 

113 

81 

87 

03 

69 

53 

59 

45 

51 

39 

45 

666 

3s) 

668 

163 

169 

109 

115 

81 

87 

63 

69 

53 

59 

45 

51 

39 

45 

668 

n 

670 

165 

171 

109 

115 

81 

87 

63 

69 

53 

59 

45 

51 

39 

45 

670 

ooo 

672 

165 

171 

109 

115 

81 

87 

65 

71 

53 

59 

45 

51 

39 

45 

672 

(SO) 

674 

165 

171 

109 

115 

81 

87 

65 

71 

53 

59 

45 

51 

39 

45 

674 

® 

676 

165 

171 

109 

115 

81 

87 

65 

71 

53 

59 

45 

51 

39 

45 

676 

ooo 

678 

107 

173 

109 

115 

81 

87 

65 

71 

53 

59 

45 

51 

39 

45 

678 

(55) 

080 

167 

173 

111 

117 

81 

87 

65 

71 

53 

59 

45 

51 

39 

45 

680 

(55) 

082 

167 

173 

111 

117 

83 

89 

65 

71 

53 

59 

45 

51 

39 

45 

682 

ooo 

084 

167 

173 

111 

117 

83 

89 

65 

71 

53 

59 

45 

51 

39 

45 

684 

(5s) 

086 

169 

175 

111 

117 

83 

89 

05 

71 

55 

61 

45 

51 

39 

45 

686 

(55) 

688 

169 

175 

111 

117 

83 

89 

65 

71 

55 

01 

47 

53 

39 

45 

688 

000 

690 

169 

175 

111 

117 

83 

89 

65 

71 

55 

61 

47 

53 

41 

47 

690 

(as) 

692 

169 

175 

113 

119 

83 

89 

67 

73 

55 

61 

47 

53 

41 

47 

692 

(55) 

694 

171 

177 

113 

119 

83 

89 

67 

73 

55 

61 

47 

53 

41 

47 

694 

ooo 

696 

171 

177 

113 

119 

83 

89 

67 

73 

55 

61 

47 

53 

41 

47 

696 

53 

698 

171 

177 

113 

119 

85 

91 

67 

73 

55 

61 

47 

53 

41 

47 

698 

(55) 

700 

171 

177 

113 

119 

85 

91 

67 

73 

55 

61 

47 

53 

41 

47 

700 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute 
magnitude  of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  TRIPLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-ENTRANCY 

No.OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

m 
cc 
o 

4 

POLES 

6 

POLES 

8 

POLES 

10 

POLES 

12 
POLES 

14 

POLES 

16 

POLES 

LonaNoo 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

o 

6 

z 

ooo 

702 

173 

179 

113 

119 

85 

91 

67 

73 

55 

61 

47 

53 

41 

47 

!  702 

(22) 

704 

173 

179 

115 

121 

85 

91 

67 

73 

55 

61 

47 

53 

41 

47 

704 

m 

706 

173 

179 

115 

121 

85 

91 

67 

73 

55 

61 

47 

53 

41 

47 

706 

ooo 

708 

173 

17',) 

115 

121 

85 

91 

67 

73 

55 

61 

47 

53 

41 

47 

708 

SSL 

710 

175 

181 

115 

121 

85 

91 

67 

73 

57 

63 

47 

53 

41 

47 

710 

(22) 

712 

175 

181 

115 

121 

85 

91 

69 

75 

57 

63 

47 

53 

41 

47 

712 

ooo 

714 

175 

181 

115 

121 

87 

93 

69 

75 

57 

63 

47 

53 

41 

47 

714 

M 

716 

175 

181 

117 

123 

87 

93 

69 

75 

57 

63 

49 

55 

41 

47 

716 

(M) 

718 

177 

183 

117 

123 

87 

93 

69 

75 

57 

63 

49 

55 

41 

47 

718 

ooo 

720 

177 

183 

117 

123 

87 

93 

69 

75 

57 

63 

49 

55 

41 

47 

720 

(22) 

722 

177 

183 

117 

123 

87 

93 

69 

75 

57 

63 

49 

55 

43 

49 

722 

(M) 

724 

177 

183 

117 

123 

87 

93 

69 

75 

57 

63 

49 

55 

43 

49 

724 

000 

72(j 

179 

185 

117 

123 

87 

93 

69 

75 

57 

63 

49 

55 

43 

49 

726 

(5s) 

728 

179 

185 

119 

125 

87 

93 

69 

75 

57 

63 

49 

55 

43 

49 

728 

(aa) 

730 

179 

185 

119 

125 

89 

95 

69 

75 

57 

63 

49 

55 

43 

49 

730 

ooo 

732 

179 

185 

119 

125 

89 

95 

71 

77 

57 

63 

49 

55 

43 

49 

732 

(M) 

734 

181 

187 

119 

125 

89 

95 

71 

77 

59 

65 

49 

55 

43 

49 

734 

(22) 

736 

181 

187 

11!) 

125 

89 

95 

71 

77 

59 

65 

49 

55 

43 

49 

736 

ooo 

738 

181 

187 

119 

125 

89 

95 

71 

77 

59 

65 

49 

55 

43 

49 

738 

(as) 

740 

181 

187 

121 

127 

89 

95 

71 

77 

59 

65 

49 

55 

43 

49 

740 

(as) 

742 

183 

189 

121 

127 

89 

95 

71 

77 

59 

65 

49 

55 

43 

49 

742 

ooo 

74_4 

183 

189 

121 

127 

89 

95 

71 

77 

59 

65 

51 

57 

43 

49 

744 

(M) 

746 

183 

1'89 

_121 

127 

91 

97 

71 

77 

59 

65 

51 

57 

43 

49 

746 

CSS) 

748 

183 

189 

121 

127 

91 

97 

71 

77 

59 

65 

51 

57 

43 

49 

748 

000 

750 

185 

191 

121 

127 

91 

97 

71 

77 

59 

65 

51 

57 

43 

49 

750 

<n> 

752 

185 

191 

123 

129 

91 

97 

73 

79 

59 

65 

51 

57 

43 

49 

752 

(aa) 

754 

185 

191 

123 

129 

91 

97 

73 

79 

59 

65 

51 

57 

45 

51 

754 

000 

756 

185 

191 

123 

129 

91 

97 

73 

79 

59 

65 

51 

57 

45 

51 

756 

(5a) 

758 

187 

193 

123 

129 

91 

97 

73 

79 

61 

67 

51 

57 

45 

51 

758 

25 

760 

187 

193 

123 

129 

91 

97 

73 

79 

61 

67 

51 

57 

45 

51 

760 

ooo 

762 

187 

193 

123 

129 

93 

99 

73 

79 

61 

67 

51 

57 

45 

51 

762 

(aa) 

764 

187 

193 

125 

131 

93 

99 

73 

79 

61 

67 

51 

57 

45 

51 

764 

(22) 

766 

189 

195 

125 

131 

93 

99 

73 

79 

61 

67 

51 

57 

45 

51 

766 

ooo 

768 

189 

195 

125 

131 

93 

99 

73 

79 

61 

67 

51 

57 

45 

51 

768 

(aa) 

770 

189 

195 

125 

131 

93 

90 

73 

79 

61 

67 

51 

57. 

45 

51 

770 

(aa) 

772 

189 

195 

125 

131 

93 

99 

75 

81 

61 

67 

53 

59 

45 

51  . 

772 

000 

774 

191 

197 

125 

131 

93 

99 

75 

81 

61 

67 

53 

59 

45 

51 

774 

(aa) 

776 

191 

197 

127 

133 

93 

99 

75 

81 

61 

67 

53 

59 

45 

51 

776 

(ss) 

778 

191 

197 

127 

133 

95 

101 

75 

81 

61 

67 

53 

59 

45 

51 

778 

ooo 

780 

191 

197 

127 

133 

95 

101 

75 

81 

61 

67 

53 

59 

45 

51 

780 

(22) 

782 

193 

199 

127 

133 

95 

101 

75 

81 

63 

69 

53 

59 

45 

51 

782 

(2fi) 

784 

193 

199 

127 

133 

95 

101 

75 

81 

63 

69 

53 

59 

45 

51 

784 

ooo 

786 

193 

199 

127 

133 

96 

101 

75 

81 

03 

69 

53 

59 

47 

53 

786 

(52) 

788 

193 

199 

129 

135 

95 

101 

75 

81 

63 

69 

53 

59 

47 

53 

788 

55 

790 

195 

201 

129 

135 

95 

101 

75 

81 

63 

69 

53 

59 

47 

53 

790 

000 

792 

195 

201 

129 

135 

95 

101 

77 

83 

63 

69 

53 

59 

47 

53 

792 

(22) 

71)4 

195 

201 

129 

135 

97 

103 

77 

83 

63 

69 

53 

59 

47 

53 

794 

(22) 

796 

195 

201 

129 

135 

97 

103 

77 

83 

63 

69 

53 

59 

47 

53 

796 

ooo 

798 

197 

203 

129 

135 

97 

103 

77 

83 

63 

69 

53 

59 

47 

53 

798 

(22) 

800 

197 

203 

131 

137 

97 

103 

77 

83 

63 

69 

55 

61 

47 

53 

800 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute 
magnitude  of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  TRIPLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-ENTRANCY 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

£ 
o 

4 

POLES 

6 

POLES 

8 

POLES 

10 

POLES 

12 

POLES 

14 
POLES 

16 

POLES 

CONDUC1 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

O 
6 

z 

(SS) 

802 

197 

203 

131 

137 

97 

103 

77 

83 

63 

69 

55 

61 

47 

53 

802 

ooo 

804 

197 

203 

131 

137 

97 

103 

77 

83 

63 

69 

55 

61 

47 

53 

804 

(ss) 

806 

199 

205 

131 

137 

97 

103 

77 

83 

65 

71 

55 

61 

47 

53 

806 

(ss) 

808 

199 

205 

131 

137 

97 

103 

77 

83 

65 

71 

55 

61 

47 

53 

808 

ooo 

810 

199 

205 

131 

137 

99 

105 

77 

83 

65 

71 

55 

61 

47 

53 

810 

(8) 

812 

199 

205 

133 

139 

99 

105 

79 

85 

65 

71 

55 

61 

47 

53 

812 

m 

814 

201 

207 

133 

139 

99 

105 

79 

85 

65 

71 

55 

61 

47 

53 

814 

ooo 

816 

201 

207 

133 

139 

99 

105 

79 

85 

65 

71 

55 

61 

47 

53 

816 

(55) 

818 

201 

207 

133 

139 

99 

105 

71) 

85 

65 

71 

55 

61 

49 

55 

818 

CM) 

820 

201 

207 

133 

139 

99 

105 

79 

85 

65 

71 

55 

61 

49 

55 

820 

ooo 

822 

203 

209 

133 

139 

99 

105 

79 

85 

65 

71 

55 

61 

49 

55 

822 

SaJ 

824 

203 

209 

135 

141 

99 

105 

79 

85 

65 

71 

55 

61 

49 

55 

824 

Ss) 

826 

203 

209 

135 

141 

101 

107 

79 

85 

65 

71 

55 

61 

49 

55 

826 

ooo 

828 

203 

209 

135 

141 

.101 

107 

79 

85 

65 

71 

57 

63 

49 

55 

828 

(Sfl) 

830 

205 

211 

135 

141 

101 

107 

79 

85 

67 

73 

57 

63 

49 

55 

830 

(&) 

832 

205 

211 

135 

141 

101 

107 

81 

87 

67 

73 

57 

63 

49 

55 

832 

ooo 

834 

205 

211 

135 

141 

101 

107 

81 

87 

67 

73 

57 

63 

49 

55 

834 

(M) 

836 

205 

211 

137 

143 

101 

107 

81 

87 

67    ' 

73 

57 

63 

49 

55 

836 

(2SJ 

838 

207 

213 

137 

143 

101 

107 

81 

87 

67 

73 

57 

63 

49 

55 

838 

ooo 

840 

207 

213 

137 

143 

101 

107 

81 

87 

67 

73 

57 

63 

49 

55 

840 

(SS) 

842 

207 

213 

137 

143 

103 

109 

81 

87 

67 

73 

57 

63 

49 

55 

842 

(SS) 

844 

207 

213 

137 

143 

103 

109 

81 

87 

67 

73 

57 

63 

49 

55 

844 

ooo 

84l> 

209 

215 

137 

143 

103 

109 

81 

87 

67 

73 

57 

63 

49 

55 

846 

®) 

848 

209 

215 

139 

145 

103 

109 

81 

87 

67 

73 

57 

63 

49 

55 

848 

(as) 

850 

209 

215 

139 

145 

103 

109 

81 

87 

67 

73 

57 

63 

51 

57 

850 

ooo 

852 

209 

215 

139 

145 

103 

109 

83 

89 

67 

73 

57 

63 

51 

57 

852 

(M) 

854 

211 

217 

139 

145 

103 

109 

83 

89 

69 

75 

57 

63 

51 

57 

854 

®) 

856 

211 

217 

139 

145 

103 

109 

83 

89 

69 

75 

59 

65 

51 

57 

856 

ooo 

858 

211 

217 

139 

145 

105 

111 

83 

89 

69 

75 

59 

65 

51 

57 

858 

(SS) 

860 

211 

217 

141 

147 

105 

111 

83 

89 

69 

75 

59 

65 

51 

57 

860 

(S3) 

862 

213 

219 

141 

147 

105 

111 

83 

89 

69 

75 

59 

65 

51 

57 

862 

ooo 

864 

213 

219 

141 

147 

105 

111 

83 

89 

69 

75 

59 

65 

51 

57 

864 

(52) 

860 

213 

219 

141 

147 

105 

111 

83 

89 

69 

75 

59 

65 

51 

57 

866 

(SS) 

868 

213 

219 

141 

147 

105 

111 

83 

89 

69 

75 

59 

65 

51 

57 

868 

ooo 

870 

215 

221 

141 

147 

105 

111 

83 

89 

69 

75 

59 

65 

51 

57 

870 

(33) 

872 

215 

221 

143 

149 

105 

111 

85 

91 

69 

75 

59 

65 

51 

57 

872 

(S3) 

874 

215 

221 

143 

149 

107 

113 

85 

91 

69 

75 

59 

65 

51 

57 

874 

ooo 

876 

215 

221 

143 

149 

107 

113 

85 

91 

69 

75 

59 

65 

51 

57 

876 

GOD 

878 

217 

223 

143 

149 

107 

113 

85 

91 

71 

77 

59 

65 

51 

57 

878 

(S3) 

880 

217 

223 

143 

149 

107 

113 

85 

91 

71 

77 

59 

65 

51 

57 

880 

ooo 

882 

217 

223 

143 

149 

107 

113 

85 

91 

71 

77 

59 

65 

53 

59 

882 

<SD 

884 

217 

223 

145 

151 

107 

113 

85 

91 

71 

77 

61 

67 

53 

59 

884 

Sfl) 

886 

219 

225 

145 

151 

107 

113 

85 

91 

71 

77 

61 

67 

53 

59 

886 

OOO 

888 

219 

225 

145 

151 

107 

113 

85 

91 

71 

77 

61 

67 

53 

59 

888 

(5ft) 

890 

219 

225 

145 

151 

109 

115 

85 

91 

71 

77 

61 

67 

53 

59 

890 

(2ft) 

892 

219 

225 

145 

151 

109 

115 

87 

93 

71 

77 

61 

67 

53 

59 

892 

ooo 

894 

221 

227 

145 

151 

109 

115 

87 

93 

71 

77 

61 

67 

53 

59 

894 

i& 

896 

221 

227 

147 

153 

109 

115 

87 

93 

71 

77 

61 

67 

53 

59 

896 

(as) 

898 

221 

227 

147 

153 

109 

115 

87 

93 

71 

77 

61 

67 

53 

59 

898 

ooo 

900 

221 

227 

147 

153 

109 

115 

87 

93 

71 

77 

61 

67 

53 

59 

900 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute 
magnitude  of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  TRIPLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-ENTRANCY 

CO 

• 
o 

FRONT  AND  BACK  PITCHES 

No.  OF  CONDUCTORS 

No.  OF  CONDUCT 

4 
POLES 

6 
POLES 

8 

POLES 

10 

POLES 

12 

POLES 

14 

POLES 

16 

POLES 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

(as) 

902 

223 

229 

147 

153 

109 

115 

87 

93 

73 

79 

61 

67 

53 

59 

902 

CM) 

904 

223 

229 

147 

153 

109 

115 

87 

93 

73 

79 

61 

67 

53 

59 

904 

ooo 

906 

223 

229 

147 

153 

111 

117 

87 

93 

73 

79 

61 

67 

53 

59 

906 

(M) 

DOS 

223 

229 

149 

155 

111 

117 

87 

93 

73 

79 

01 

67 

53 

59 

,908 

m 

910 

225 

231 

149 

155 

111 

117 

87 

93 

73 

79 

0,1 

67 

53 

59 

910 

000 

912 

225 

231 

149 

155 

111 

117 

89 

95 

73 

79 

63 

69 

53 

59 

912 

(55) 

914 

225 

231 

149 

155 

111 

117 

89 

95 

73 

79 

63 

69 

55 

61 

914 

CM) 

916 

225 

231 

149 

155 

111 

117 

89 

1)5 

73 

79 

63 

69 

55 

61 

916 

ooo 

918 

227 

233 

149 

155 

111 

117 

89 

95 

73 

79 

63 

69 

55 

61 

918 

55 

920 

227 

233 

151 

157 

111 

117 

89 

95 

73 

79 

63 

69 

55 

61 

920 

(5s) 

922 

227 

233 

151 

157 

113 

119 

89 

95 

73 

79 

63 

69 

oo 

61 

922 

000 

924 

227 

233 

151 

157 

113 

119 

89 

95 

73 

79 

03 

69 

CK 
*)O 

61 

924 

(M) 

jm 

229 

235 

151 

157 

113 

119 

89 

95 

75 

81 

03 

69 

55 

61 

926 

<§Sl 

92S 

229 

235 

151 

157 

113 

119 

89 

95 

75 

81 

63 

69 

55 

61 

928 

ooo 

930 

229 

235 

151 

157 

113 

119 

89 

95 

75 

81 

63 

69 

55 

61 

930 

(M) 

932 

229 

2:!  5 

153 

151) 

113 

119 

91 

97 

75 

81 

63 

69 

55 

61 

932 

CM) 

934 

231 

237 

153 

159 

113 

11',) 

91 

1)7 

75 

81 

63 

69 

55 

61 

934 

ooo 

936 

231 

237 

153 

159 

113 

119 

91 

1)7 

75 

81 

63 

69 

55 

61 

936 

CM) 

938 

231 

237 

153 

159 

115 

121 

91 

97 

75 

81 

63 

69 

55 

61 

938  . 

(28L 

940 

231 

237 

153 

151) 

115 

121 

91 

97 

75 

81 

65 

71 

55 

61 

940 

ooo 

1)42 

233 

239 

153 

159 

115 

121 

91 

97 

75 

81 

65 

71 

55 

61 

942 

(55) 

944 

233 

239 

155 

161 

115 

121 

91 

97 

75 

81 

65 

71 

55 

61 

944 

CM) 

946 

233 

239 

155 

161 

115 

121 

91 

97 

75 

81 

65 

71 

57 

63 

946 

ooo 

948 

233 

239 

155 

161 

115 

121 

91 

97 

75 

81 

65 

71 

57 

63 

948 

CM) 

950 

235 

241 

155 

161 

115 

JTC 

91 

97 

77 

83 

65 

71 

57 

63 

950 

C5a) 

952 

235 

241 

155 

161 

115 

121 

93 

99 

77 

83 

65 

71 

57 

63 

952 

000 

954 

235 

241 

155 

161 

117 

123 

93 

99 

77 

83 

65 

71 

57 

63 

r  954 

CM) 

956 

235 

241 

157 

103 

117 

123 

93 

99 

77 

83 

65 

71 

57 

63 

956 

m 

958 

237 

243 

157 

163 

117 

123 

1»3 

99 

77 

83 

65 

71 

57 

63 

958 

000 

960 

237 

243 

157 

163 

117 

123 

93 

99 

77 

83 

65 

71 

57 

63 

960 

(aa) 

962 

237 

243 

157 

163 

117 

123 

93 

99 

77 

83 

65 

71 

57 

63 

962 

CM) 

964 

237 

213 

157 

163 

117 

123 

93 

99 

77 

83 

65 

71 

57 

63 

964 

000 

906 

239 

245 

157 

163 

1L7 

123 

93 

99 

77 

83 

05 

71 

57 

63 

966 

(as) 

%8T 

239 

245 

159 

165 

117 

123 

93 

99 

77 

83 

67 

73 

57 

63 

968 

CM) 

970 

239 

245 

159 

105 

119 

125 

93 

99 

77 

83 

67 

73 

57 

63 

970 

000 

972 

239 

245 

159 

105 

119 

125 

95 

101 

77 

83 

67 

73 

57 

63 

972 

CM) 

974 

241 

247 

159 

165 

119 

125 

95 

101 

79 

85 

67 

73 

57 

63 

974 

CM) 

976 

241 

247 

159 

165 

119 

125 

95 

101 

79 

85 

67 

73 

57 

63 

976 

000 

978 

241 

247 

159 

165 

iiir 

125 

95 

101 

79 

85 

67 

73 

59 

65 

978 

CM) 

980 

241 

247 

161 

"107 

ni) 

125 

95 

101 

79 

85 

67 

73 

59 

65 

980 

CS9) 

982 

243 

249 

161 

167 

119 

125 

95 

101 

79 

85 

67 

73 

59 

65 

982 

ooo 

984 

243 

249 

161 

167 

119 

125 

95 

101 

79 

85 

67 

73 

59 

65 

984 

CM) 

980 

213 

249 

161 

167 

121 

127 

95 

101 

79 

85 

67 

73 

59 

65 

986 

m 

988 

243 

249 

101 

167 

121 

127 

95 

101 

79 

85 

67 

73 

59 

65 

1)88 

ooo 

990 

245 

251 

161 

167 

121 

127 

95 

101 

79 

85 

67 

73 

59 

65 

990 

CM) 

992 

245 

251 

163 

169 

121 

127 

97 

103 

79 

85 

67 

73 

59 

65 

992 

CM) 

994 

245 

251 

103 

169 

121 

127 

97 

103 

79 

85 

67 

73 

59 

65 

994 

000 

996 

245 

251 

103 

169 

121 

127 

97 

103 

79 

85 

69 

75 

59 

65 

996 

CM) 

998 

"247" 

253 

103 

169 

121 

127 

97 

103 

81 

87 

01) 

75 

59 

65 

998 

<5& 

1000 

247 

253 

163 

169 

121 

127 

97 

103 

81 

87 

69 

75 

59 

65 

1000 

Above  choree  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute 
magnitude  of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  TRIPLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-ENT  RANGY 

en 
K 

O 

FRONT  AND  BACK  PITCHES 

No.  OIF  CONDUCTORS 

CONDUC1 

4 

POLES 

6 
POLES 

8 
POLES 

10 

POLES 

12 

POLES 

14 

POLES 

16 

POLES 

O 

d 

Z 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

ooo 

1002 

247 

253 

163 

169 

123 

129 

97 

103 

81 

87 

69 

75 

59 

65 

1002 

CM) 

1004 

247 

253 

165 

171 

123 

129 

97 

103 

81 

87 

69 

75 

59 

65 

1004 

(as) 

1006 

249 

255 

165 

171 

123 

129 

97 

103 

81 

87 

69 

75 

59 

65 

1006 

000 

1008 

249 

255 

165 

171 

123 

129 

97 

103 

81 

87 

69 

75 

59 

65 

1008 

(sa) 

1010 

249 

255 

165 

171 

123 

129 

97 

103 

81 

87 

69 

75 

61 

67 

1010 

CM) 

1012 

249 

255 

165 

171 

123 

129 

99 

105 

81 

87 

69 

75 

61 

67 

1012 

000 

1014 

251 

257 

165 

171 

123 

129 

99 

105 

81 

87 

69 

75 

61 

67 

1014 

fig) 

1016 

251 

257 

167 

173 

123 

129 

99 

105 

81 

87 

69 

75 

61 

67 

1016 

(as) 

1018 

251 

257 

167 

173 

125 

131 

99 

105 

81 

87 

G9 

75 

61 

67 

1018 

ooo 

1020 

251 

257 

167 

173 

125 

131 

99 

105 

81 

87 

69 

75 

61 

67 

1020 

(5s) 

1022 

253 

259 

167 

173 

125 

131 

99 

105 

83 

89 

69 

75 

61 

67 

1022 

<Sa) 

1024 

253 

259 

167 

173 

125 

131 

99 

105 

83 

89 

71 

TL 

61 

67 

1024 

ooo 

1026 

253 

259 

167 

173 

125 

131 

99 

105 

83 

89 

71 

77 

61 

67 

1026 

55 

1028 

253 

259 

169 

175 

125 

131 

99 

105 

83 

89 

71 

77 

61 

67 

1028 

CM) 

1030 

255 

261 

169 

175 

125 

131 

99 

105 

83 

89 

71 

77 

61 

67 

1030 

ooo 

1032 

255 

261 

169 

175 

125 

131 

101 

107 

83 

89 

71 

77 

61 

67 

1032 

SJD 

1034 

255 

261 

169 

175 

127 

133 

101 

107 

83 

89 

71 

77 

61 

67 

1034 

CM) 

1036 

255 

261 

169 

175 

127 

133 

101 

107 

83 

89 

__71 

77 

61 

67 

1036 

ooo 

"1038" 

257 

263 

169 

175 

127 

133 

101 

107 

83 

89 

71 

77 

61 

67 

1038 

CM) 

1040 

257 

263 

171 

177 

127 

133 

101 

107 

83 

89 

71 

77 

61 

67 

1040 

Caa) 

1042 

.257 

2G3 

171 

177 

127 

133 

101 

107 

813 

89 

71 

77 

63 

69 

1042 

ooo 

1044 

257 

263 

171 

177 

127 

133 

101 

107 

83 

89 

71 

77 

63 

69 

1044 

<Sa) 

1046 

259 

265 

171 

177 

127 

133 

101 

.107 

85 

91 

71 

77 

63 

69 

1046 

3s 

1048 

259 

265 

171 

177 

127 

133 

101 

107 

85 

91 

71 

77 

63 

69 

1048 

ooo 

1050 

259 

265 

171 

177 

129 

135 

101 

107 

85 

91 

71 

77 

63 

69 

1050 

CM) 

1052 

259 

265 

173 

179 

129 

135 

103 

109 

85 

91 

73 

79 

63 

69 

1052 

(as) 

1054 

261 

267 

173 

179 

129 

135 

103 

109 

85 

91 

73 

79 

63 

69 

1054 

ooo 

1056 

261 

267 

173 

179 

129 

135 

103 

109 

85 

91 

73 

79 

63 

69 

105G 

(as) 

1058 

261 

267 

173 

179 

129 

135 

103 

109 

85 

91 

73 

79 

63 

69 

1058 

(M) 

1060 

261 

267 

173 

179 

129 

135 

103 

109 

85 

91 

73 

79 

63 

69 

1060 

ooo 

1062 

263 

269 

173 

179 

129 

135 

103 

109 

85 

91 

73 

79 

63 

69 

1062 

CM) 

1064 

263 

269 

175 

181 

129 

135 

103 

109 

85 

91 

73 

79 

63 

69 

1064 

cea) 

1006 

2f§ 

269 

175 

181 

131 

137 

103 

109 

85 

91 

73 

79 

63 

69 

1066 

ooo 

ions 

2G3 

269 

175 

181 

131 

137 

103 

109 

85 

91 

73 

79 

63 

69 

1068 

CM) 

1070 

265 

271 

175 

181 

131 

137 

103 

109 

87 

93 

73 

79 

63 

69 

1070 

(22) 

1072 

265 

271 

175 

181 

131 

137 

105 

111 

87 

93 

73 

79 

63 

69 

1072 

ooo 

1074 

265 

271 

175 

181 

131 

137 

105 

111 

87 

98 

73 

79 

65 

71 

1074 

CM) 

107G 

265 

271 

177 

183 

131 

137 

105 

111 

87 

93 

73 

79 

65 

71 

107G 

sa> 

1078 

267 

273 

177 

183 

131 

137 

105 

111 

87 

93 

73 

79 

65 

71 

1078 

ooo 

10HO 

267 

273 

177 

183 

131 

137 

105 

111 

87 

93 

75 

81 

65 

71 

10SO 

CM) 

1082 

267 

273 

177 

183 

133 

139 

105 

111 

87 

93 

75 

81 

65 

71 

1082 

cas) 

1084 

267 

273 

177 

183 

133 

139 

105 

111 

87 

93 

75 

81 

65 

71 

1084 

ooo 

1086 

269 

275 

177 

183 

133 

139 

105 

111 

87 

93 

75 

81 

65 

71 

1086 

CM) 

1088 

269 

275 

179 

185 

133 

139 

105 

111 

87 

93 

75 

81 

65 

71 

1088 

CM) 

1090 

269 

275 

179 

185 

133 

139 

105 

111 

87 

93 

75 

81 

65 

71 

1090 

000 

1092 

269 

275 

171) 

185 

133 

139 

107 

113 

87 

93 

75 

81 

65 

71 

1092 

(Sa) 

1094 

271 

277 

179 

185 

133 

189 

107 

113 

89 

1)5 

75 

81 

65 

71 

1094 

CM) 

1096 

271 

277 

179 

185 

133 

139 

107 

113 

89 

95 

75 

81 

65 

71 

1096 

ooo 

1098 

271 

277 

179 

185 

135 

141 

107 

113 

89 

95 

75 

81 

65 

71 

1098 

(M) 

1100 

271 

277 

181 

187 

135 

141 

107 

113 

89 

95 

75 

81 

65 

71 

1100 

Above  choice  of  Pitches  wjll  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute 
magnitude  of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  TRIPLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-ENTRANCY 

No  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

en 

DC 

o 

4. 

POLES 

6 

POLES 

8 

POLES 

10 

POLES 

12 

POLES 

14 

POLES 

16 

POLES 

CONDUCl 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

h. 

0 

o 

Z 

fSSt 

1102 

273 

279 

181 

187 

135 

141 

107 

113 

89 

95 

75 

81 

65 

71 

1102 

ooo 

11D1 

273 

279 

181 

187 

135 

141 

107 

113 

89 

95 

75 

81 

65 

71 

1104 

(3D 

1106 

273 

279 

181 

187 

135 

141 

107 

113 

89 

95 

75 

SI 

07 

73 

1106 

(2a) 

1108 

273 

279 

181 

187 

135 

141 

107 

113 

89 

95 

77 

83 

67 

73 

1108 

ooo 

1110 

275 

281 

181 

187 

135 

141 

107 

113 

89 

95 

77 

83 

67 

73 

1110 

(&&) 

1112 

275 

281 

183 

189 

135 

141 

109 

115 

89 

95 

77 

83 

67 

73 

1112 

<3a) 

1114 

275 

281 

183 

189 

137 

143 

109 

115 

89 

95 

77 

83 

67 

73 

1114 

ooo 

1116 

275 

281 

183 

189 

137 

143 

109 

115 

89 

95 

77 

83 

67 

73 

1116 

(ss) 

1118 

277 

283 

183 

ISO 

137 

143 

109 

115 

91 

97 

77 

83 

67 

73 

1118 

(so) 

1120 

277 

283 

183 

18!) 

137 

143 

10!) 

115 

91 

1)7 

77 

83 

67 

7;! 

1120 

ooo 

1122 

277 

283 

183 

189 

137 

143 

109 

115 

91 

97 

77 

83 

1    67 

73 

1  122 

(SA) 

1124 

277 

2S3 

185 

191 

137 

143 

109 

115 

91 

97 

77 

83 

67 

73 

1124 

(fifl) 

1126 

279 

285 

185 

191 

137 

143 

109 

115 

91 

97 

77 

83 

67 

73 

1126 

ooo 

1128 

271) 

285 

185 

191 

137 

143 

109 

115 

91 

97 

77 

83 

67 

73 

1128 

(S) 

1130 

279 

285 

185 

191 

139 

145 

109 

115 

91 

97 

77 

83 

67 

73 

1130 

(SS) 

1132 

279 

285 

185 

191 

139 

145 

111 

117 

91 

97 

77 

83 

67 

73 

1132 

ooo 

ll:tl 

281 

287 

185 

191 

139 

145 

111 

117 

1)1 

97 

77 

83 

67 

73 

1134 

(aa) 

1136 

281 

287 

187 

193 

139 

145 

111 

117 

91 

97 

79 

85 

67 

73 

1136 

(S) 

ll:!8 

281 

287 

187 

193 

139 

145 

111 

117 

91 

97 

79 

85 

69 

75 

1138 

ooo 

1140 

281 

287 

187 

193 

139 

145 

111 

117 

91 

1)7 

79 

85 

69 

75 

1140 

(Si 

1142 

283 

289 

187 

193 

139 

145 

111 

117 

93 

99 

79 

85 

69 

75 

1142 

GOD 

1144 

283 

289 

187 

193 

139 

145 

111 

117 

93 

99 

79 

85 

69 

75 

1111 

ooo 

1146 

283 

289 

187 

193 

141 

147 

111 

117 

93 

99 

79 

86 

01) 

75 

1  140 

(3D 

1148 

283 

2S1J 

189 

195 

141 

147 

111 

117 

93 

99 

79 

s.-) 

69 

75 

1148 

(5e) 

115H 

2S5 

291 

189 

195 

141 

147 

111 

117 

93 

99 

79 

85 

69 

75 

1150 

ooo 

1  1  52 

285 

291 

189 

195 

141 

147 

113 

119 

93 

99 

79 

85 

69 

75 

1152 

(3D 

1154 

285 

291 

189 

11)5 

141 

147 

113 

119 

93 

99 

79 

85 

69 

75 

1154 

GOD 

1156 

285 

291 

189 

195 

141 

147 

113 

119 

93 

99 

79 

85 

69 

75 

1156 

ooo 

1158 

287 

293 

189 

195 

Ml 

147 

113 

119 

93 

99 

79 

85 

69 

75 

1158 

GOD 

1160 

2S7 

293 

191 

197 

141 

147 

113 

119 

93 

99 

79 

85 

69 

75 

1160 

GOD 

11IJ2 

287 

293 

191 

197 

143 

149 

113 

119 

93 

99 

7!) 

85 

69 

75 

1162 

ooo 

i  Hvi 

287 

293 

191 

11)7 

143 

149 

113 

119 

93 

99 

81 

87 

69 

75 

1164 

GOD 

1  Kill 

289 

295 

191 

197 

111! 

149 

113 

119 

95 

101 

81 

87 

69 

75 

1100 

GOD 

1108 

289 

295 

191 

197 

143 

149 

113 

119 

95 

101 

81 

87 

69 

75 

1168 

ooo 

1170 

2S!> 

295 

191 

197 

143 

149 

113 

119 

95 

101 

81 

87 

71 

77 

1170 

CM) 

1172 

289 

295 

193 

199 

143 

149 

115 

121 

95 

101 

81 

87 

71 

77 

1172 

(9?) 

1171 

291 

21)7 

193 

1  1)1) 

143 

149 

115 

121 

95 

101 

81 

87 

71 

77 

1174 

ooo 

1170 

291 

297 

193 

11)1) 

143 

149 

115 

121 

95 

101 

81 

87 

71 

77 

1176 

GOD 

1178 

21)1 

297 

193 

199 

145 

151 

115 

121 

95 

101 

81 

87 

71 

77 

1178 

<S) 

1  ISO 

291 

297 

193 

199 

145 

151 

115 

121 

95 

101 

81 

87 

71 

77 

1180 

ooo 

1  1  x  -> 

293 

299 

193 

199 

145 

151 

115 

121 

95 

101 

81 

87 

71 

77 

1182 

GOD 

3184 

293 

21)1) 

195 

201 

145 

151 

115 

121 

95 

101 

81 

87 

71 

77 

1  ]  SI 

(aa) 

1186 

293 

299 

195 

201 

145 

151 

115 

121 

1)5 

101 

81 

87 

71 

77 

1186 

OOO 

1188 

21)3 

29!) 

195 

201 

145 

151 

115 

121 

95 

101 

81 

87 

71 

77 

1188 

SR) 

1190 

21)5 

301 

195 

201 

145 

151 

115 

121 

97 

103 

81 

87 

71 

77 

1190 

Sa) 

1192 

2!>5 

301 

195 

201 

145 

151 

117 

123 

97 

103 

83 

89 

71 

77 

1192 

ooo 

11'.)  1 

21)5 

301 

195 

201 

147 

153 

117 

123 

97 

103 

83 

89 

71 

77 

1194 

(Sa) 

ll'.IO 

295 

301 

197 

203 

147 

153 

117 

123 

97 

103 

83 

89 

71 

77 

1196 

fiS 

1198 

2'.»7 

:jo:s 

197 

203 

147 

153 

117 

123 

97 

103 

83 

89 

71 

77 

1198 

ooo 

1200 

297 

303 

197 

203 

147 

153 

117 

123 

97 

103 

83 

89 

71 

77 

1200 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute 
magnitude  of  average  pitch  may  be  Varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  TRIPLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-ENTRANCY 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

No.OF  CONDUCTORS 

4 
POLES 

6 

POLES 

8 

POLES 

10 

POLES 

12 

POLES 

14 

POLES 

16 

POLES 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

<SD 

1202 

297 

303 

197 

203 

147 

153 

117 

123 

97 

103 

83 

89 

73 

79 

1202 

(55) 

1204 

297 

303 

197 

203 

147 

153 

117 

123 

97 

103 

83 

89 

73 

79 

1204 

000 

1206 

299 

305 

197 

203 

147 

153 

117 

123 

97 

103 

83 

89 

73 

79 

1206 

(55) 

1208 

299 

305 

199 

205 

147 

153 

117 

123 

97 

103 

83 

89 

73 

79 

1208 

(55) 

1210 

299 

305 

199 

205 

149 

155 

117 

123 

97 

103 

83 

89 

73 

79 

1210 

000 

1212 

299 

305 

199 

205 

149 

155 

119 

125 

97 

103 

83 

89 

73 

79 

1212 

(55) 

1214 

301 

307 

199 

205 

149 

155 

119 

125 

99 

105 

83 

89 

73 

79 

1214 

(55) 

1216 

301 

307 

199 

205 

149 

155 

119 

125 

99 

105 

83 

Bi. 

73 

79 

1216 

ooo 

1218 

301 

307 

199 

205 

149 

155 

119 

125 

99 

105 

83 

89 

73 

79 

1218 

(55) 

1220 

801 

307 

201 

207 

149 

155 

119 

125 

99 

105 

85 

91 

73 

79 

1220 

(55) 

1222 

303 

309 

201 

207 

149 

155 

119 

125 

99 

105 

85 

91 

73 

79 

1222 

000 

1224 

303 

309 

201 

207 

149 

155 

119 

125 

99 

105 

85 

91 

73 

79 

1224 

(55) 

1226 

303 

309 

201 

207 

151 

157 

119 

525 

99 

105 

85 

91 

73 

79 

1226 

(SAL. 

1228 

303 

309 

201 

207 

151 

157 

119 

125 

99 

105 

85 

_21   . 

73 

79 

1228 

000 

1230 

305 

311 

201 

207 

151 

157 

119 

125 

9!) 

105 

85 

91 

73 

79 

1230 

(55) 

1232 

305 

311 

203 

209 

151 

157 

121 

127 

99 

105 

85 

91 

73 

79 

1232 

(55) 

1234 

305 

311 

203 

209 

151 

157 

121 

127 

99 

105 

85 

91 

75 

81 

1234 

ooo 

1236 

305 

311 

203 

209 

151 

157 

121 

127 

99 

105 

85 

91 

75 

81 

1236 

M 

1238 

307 

313 

203 

209 

151 

157 

121 

127 

101 

107 

85 

91 

75 

81 

1238 

(55) 

1240 

307 

313 

203 

209 

151 

157 

121 

127 

101 

107 

85 

91 

75 

81 

1240 

000 

1242 

307 

313 

203 

209 

153 

159 

121 

127 

101 

107 

85 

91 

75 

81 

1242 

S5) 

1244 

307 

313 

205 

211 

153 

159 

121 

127 

101 

107 

85 

91 

75 

81 

1244 

(55) 

1246 

309 

315 

205 

211 

153 

159 

121 

127 

101 

107 

85 

91 

75 

81 

1246 

ooo 

1248 

309 

315 

205 

211 

153 

159 

121 

127 

101 

107 

87 

93 

75 

81 

1248 

(55) 

1250 

309 

315 

205 

211 

153 

159 

121 

127 

101 

107 

87 

93 

75 

81 

1250 

(55) 
ooo 

1252 

309 

315 

205 

211 

153 

159 

123 

129 

101 

107 

87 

93 

75 

81 

1252 

1254 

311 

317 

205 

211 

153 

159 

123 

129 

101 

107 

87 

93 

75 

81 

1254 

(55) 

1256 

311 

317 

207 

213 

153 

159 

123 

129 

101 

107 

87 

93 

75 

81 

1256 

(55) 

1258 

311 

317 

207 

213 

155 

161 

123 

129 

101 

107 

87 

93 

75 

81 

1258 

ooo 

1260 

311 

317 

207 

213 

155 

161 

123 

129 

101 

107 

87 

93 

75 

81 

1260 

(55) 

1262 

313 

319 

207 

213 

165 

161 

123 

129 

103 

109 

87 

93 

75 

81 

1262 

(55) 

1264 

313 

319 

207 

213 

155 

161 

123 

129 

103 

109 

87 

93 

75 

81 

1264 

ooo 

126G 

313 

319 

207 

213 

155 

161 

123 

129 

103 

109 

87 

93 

77 

83 

1266 

rj8>_ 

(55) 

12(18 

313 

319 

209 

215 

155 

161 

123 

129 

103 

109 

87 

93 

77 

83 

1268 

1270 

315 

321 

209 

215 

155 

161 

123 

129 

108 

109 

87 

98 

77 

83 

1270 

000 

1272 

315 

321 

209 

215 

155 

161 

125 

131 

103 

109 

87 

93 

77 

83 

1272 

(55) 

1274 

315 

321 

209 

215 

157 

163 

125 

131 

103 

109 

87 

93 

77 

83 

1274 

(52) 

1276 

315 

32  1. 

209 

215 

157 

163 

125 

131 

103 

109 

89 

95 

77 

83 

1216 

ooo 

1278 

317 

323 

209 

215 

157 

163 

125 

131 

103 

109 

89 

95 

77 

83 

1278 

(55) 

1280 

317 

323 

211 

217 

157 

163 

125 

131 

103 

109 

89 

95 

77 

83 

1280 

(55) 

1282 

317 

323 

211 

217 

157 

163 

125 

131 

103 

109 

89 

95 

77 

83 

1282 

000 

1284 

317 

323 

211 

217 

157 

163 

125 

131 

103 

109 

89 

95 

77 

83 

1284 

<S5) 

1286 

319 

325 

211 

217 

157 

163 

125 

131 

105 

111 

89 

95 

77 

83 

1286 

(55) 

12X8 

319 

325 

211 

217 

157 

163 

125 

131 

105 

111 

89 

95 

77 

83 

12S8 

ooo 

1290 

319 

325 

211 

217 

159 

165 

125 

131 

105 

111 

89 

95 

77 

83 

1290 

(55) 

1292_ 

319 

325 

213 

219 

159 

165 

127 

133 

105 

111 

89 

95 

77 

83 

1292 

(55) 

1204 

321 

327 

213 

219 

159 

165 

127 

133 

105 

111 

89 

95 

77 

83 

1294 

000 

1290 

321 

327 

213 

219 

159 

165 

127 

133 

105 

in 

89 

95 

77 

83 

1296 

(55) 

1298 

321 

327 

213 

219 

159 

165 

127 

133 

105 

111 

89 

95 

79 

85 

1298 

(55) 

1300 

321 

327 

213 

219 

159 

165 

127 

133 

105 

ill 

89 

95 

79 

85 

1300 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute 
magnitude  of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  TRIPLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-ENTRANCY 

NO.OFCONDUCTORS 

FRONT  AND  BACK  PITCHES 

•CONDUCTORS 

4 

POLES 

6 

POLES 

8 

POLES 

10 

POLES 

12 
POLES 

14 
POLES 

16 
POLES 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

O 

6 
z 

OOO 

1302 

323 

329 

213 

219 

159 

165 

127 

133 

105 

111 

89 

95 

79 

85 

1302 

(22) 

1304 

323 

329 

215 

221 

159 

165 

127 

133 

105 

in 

91 

97 

79 

85 

1304 

(22) 

1306 

323 

329 

215 

221 

161 

167 

127 

133 

105 

111 

91 

97 

70 

85 

1306 

OOO 

1308 

323 

329 

215 

221 

161 

167 

127 

133 

105 

111 

91 

97 

71) 

85 

1308 

(22) 

1310 

325 

331 

215 

221 

161 

167 

127 

133 

107 

113 

91 

97 

is 

85 

1310 

(22) 

1312 

325 

331 

215 

221 

161 

167 

129 

135 

107 

113 

91 

97 

79 

85 

1312 

OOO 

1314 

325 

331 

215 

221 

161 

167 

129 

135 

107 

113 

91 

97 

79 

85 

1314 

(22) 

1316 

325 

331 

217 

223 

161 

167 

129 

135 

107 

113 

91 

97 

79 

_8§_ 

1316 

(22) 

1318 

327 

333 

217 

223 

161 

167 

129 

135 

107 

113 

1)1 

97 

79 

85 

1318 

000 

1320 

327 

333 

217 

223 

161 

167 

129 

135 

107 

113 

91 

97 

79 

85 

1320 

ss 

1322 

327 

333 

217 

223 

163 

169 

129 

135 

107 

113 

91 

97 

79 

85 

1322 

(55) 

1324 

327 

333 

217 

223 

163 

169 

129 

135 

107 

113 

91 

97 

79 

85 

1324 

000 

1326 

329 

335 

217 

223 

163 

169 

129 

135 

107 

113 

91 

97 

7'.) 

85 

1326 

(22) 

1328 

321) 

335 

219 

225 

163 

169 

129 

135 

107 

113 

91 

97 

79 

85 

1328 

(20) 

1330 

329 

335 

219 

225 

163 

169 

129 

135 

107 

113 

91 

97 

81 

87 

1330 

OOO 

1332 

32'.) 

335 

219 

225 

163 

169 

131 

137 

107 

113 

93 

99 

81 

87 

1332 

(22) 

1334 

331 

337 

219 

225 

163 

169 

131 

137 

109 

115 

93 

99 

81 

87 

1334 

(22) 

1336 

331 

337 

219 

225 

163 

169 

131 

137 

109 

115 

93 

99 

81 

87 

1336 

OOO 

1338 

331 

337 

219 

225 

165 

171 

131 

137 

109 

115 

93 

99 

81 

_83_ 

1338 

(22) 

1340 

331 

337 

221 

227 

165 

171 

131 

137 

109 

115 

93 

99 

81 

87 

1340 

(55) 

1342 

333 

339 

221 

227 

165 

171 

131 

137 

109 

115 

93 

1)9 

81 

87 

1342 

000 

1344 

333 

339 

221 

227 

165 

171 

131 

137 

109 

115 

93 

99 

81 

87 

1344 

(55) 

1346 

333 

339 

221 

227 

165 

171 

131 

137 

109 

115 

1)3 

99 

81     . 

87 

1346 

(ss) 

1348 

333 

339 

221 

227 

165 

171 

131 

137 

109 

115 

93 

99 

81 

87 

1348 

OOO 

1350 

335 

341 

221 

227 

165 

171 

131 

137 

109 

115 

93 

99 

81 

87 

1350 

(22) 

1352 

335 

341 

223 

229 

165 

171 

133 

139 

109 

115 

93 

99 

81 

87 

1352 

(22) 

1354 

335 

341 

223 

229 

167 

173 

133 

139 

109 

115 

93 

1)1) 

81 

87 

1354 

OOO 

1356 

335 

341 

223 

229 

167 

173 

133 

139 

109 

115 

93 

99 

81 

87 

1356 

(sS_ 

1358 

337 

343 

223 

229 

167 

173 

133 

139 

111 

117 

93 

99 

81 

_82    . 

1358 

(22) 

1360 

337 

343 

223 

229 

167 

173 

133 

139 

111 

117 

95 

101 

81 

87 

J.360 

000 

1362 

337 

343 

223 

229 

167 

173 

133 

139 

111 

117 

95 

101 

83 

89 

1362 

(52) 

1364 

337 

343 

225 

231 

167 

173 

133 

139 

111 

117 

95 

101 

83 

89 

1304 

(22) 

13GO 

339 

345 

225 

231 

167 

173 

133 

139 

111 

117 

95 

101 

83 

89 

1366 

OOO 

1368 

339 

345 

225 

231 

167 

173 

133 

139 

111 

117 

95 

101 

83 

89 

13G8 

(22) 

1370 

339 

345 

225 

231 

169 

175 

133 

139 

111 

117 

95 

101 

83 

89 

1370 

(22) 

1372 

339 

345 

225 

231 

169 

175 

135 

141 

111 

117 

95 

101 

83 

89 

1372 

OOO 

1374 

341 

347 

225 

231 

169 

175 

135 

141 

111 

117 

95 

101 

83 

89 

1371 

(22) 

1376 

341 

347 

227 

233 

169 

175 

135 

141 

111 

117 

95 

101 

83 

89 

137(1 

(22) 

1378 

341 

347 

227 

233 

169 

175 

135 

141 

111 

117 

95 

101 

83 

89 

1378 

OOO 

1380 

341 

347 

227 

233 

169 

175 

135 

141 

111 

117 

95 

101 

83 

89 

1380 

(22) 

1382 

343 

349 

227 

233 

169 

175 

135 

141 

113 

119 

95 

101 

83 

89. 

1382 

(22) 

1384 

343 

349 

227 

233 

169 

175 

135 

141 

113 

119 

95 

101 

83 

89 

1384 

OOO 

1386 

343 

349 

227 

233 

171 

177 

135 

141 

113 

119 

95 

101 

83 

89 

ISSfi 

(22) 

1388 

343 

349 

229 

235 

171 

177 

135 

141 

113 

119 

97 

103 

83 

89 

1388 

(22) 

131)0 

345 

351 

229 

235 

171 

177 

135 

141 

113 

119 

97 

103 

83 

89 

131)0 

000 

1302 

345 

351 

229 

235 

171 

177 

137 

143 

113 

119 

97 

103 

83 

sa- 

1392 

(52) 

1394 

345 

351 

229 

235 

171 

177 

137 

143 

113 

119 

97 

103 

85 

il 

1394 

(20) 

i3'.m 

345 

351 

229 

235 

171 

177 

137 

143 

113 

119 

97 

103 

85 

91 

131)6 

OOO 

131)8 

347 

353 

229 

235 

171 

177 

137 

143 

113 

111) 

1)7 

103 

85 

1)1 

131)8 

(22) 

1400 

347 

353 

231 

237 

171 

177 

137 

143 

113 

119 

1)7 

103 

85 

91 

1400 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in.  text,  the  absolute 
magnitude  of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  TRIPLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-ENTRANCY 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

No.  OF  CONDUCTORS 

4 

POLES 

6 

POLES 

8 
POLES 

10 
POLES 

12 
POLES 

14 

POLES 

16 
POLES 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

CM) 

1402 

347 

353 

231 

237 

173 

179 

137 

143 

113 

119 

97 

103 

85 

91 

1402 

000 

1404 

m 

353 

231 

237 

173 

179 

137 

143 

113 

119 

97 

103 

85 

91 

1404 

M 

1406 

349 

355 

231 

237 

173 

179 

137 

143 

115 

121 

97 

103 

85 

91 

1406 

CM) 

1408 

349 

355 

231 

237 

173 

179 

137 

143 

115 

121 

97 

103 

85 

91 

1408 

ooo 

1410 

349 

55B 

23] 

237 

173 

179 

137 

143 

115 

121 

97 

103 

85 

91 

1410 

CM) 

1412 

349 

355 

233 

239 

173 

179 

139 

145 

115 

121 

97 

103 

85 

91 

1412 

<Hi 

1414 

351 

357 

233 

239 

173 

179 

139 

145 

115 

121 

97 

103 

85 

91 

1414 

ooo 
CM) 

1416 

851 

357 

233 

239 
239 

173 

179 

139 

145 

115 

121 

99 

105 

85 

91 

1416 

1418 

351 

357 

H3B~ 

175 

181 

139 

145 

115 

121 

99 

105 

85 

91 

1418 

CM) 

1420 

351 

357 

233 

239 

176 

181 

139 

145 

115 

121 

99 

105 

85 

91 

1420 

000 

1422 

353 

359 

233 

239 

175 

181 

139 

145 

115 

121 

99 

105 

85 

91 

1422 

(223 

1424 

353 

359 

235 

241 

175 

181 

139 

145 

115 

121 

99 

105 

85 

91 

1424 

M 

1426 

353 

•~37V9" 

235 

241 

175 

181 

139 

145 

115 

121 

99 

105 

87 

93 

1426 

000 

H28 

353 

359 

235 

241 

175 

181 

139 

145 

115 

121 

99 

105 

87 

93 

1428 

CM) 

1430 

355 

301 

235 

241 

175 

181 

139 

145 

117 

123 

99 

1(15 

87 

93 

1430 

(SD 

1432 

355 

361 

235 

241 

175 

181 

141 

147 

117 

123 

99 

105 

87 

93 

1432 

ooo 

1434 

355 

361 

235 

241 

177 

183 

141 

147 

117 

123 

99 

105 

87 

93 

1434 

(M) 

1436 

355 

361 

237 

243 

177 

183 

141 

147 

117 

123 

99 

105 

87 

93 

1436 

CM) 

1438 

357 

363 

.237 

243 

177 

183 

141 

147 

117 

123 

99 

105 

87 

93 

1438 

OOO 

1440 

357 

363 

237 

243 

177 

183 

141 

147 

117 

123 

99 

105 

87 

..'.«_  . 

1440 

CM) 

1442 

357 

3(33 

237 

243 

177 

183 

141 

1  47 

117 

123 

99 

105 

87 

93 

1442 

CM) 

1444 

357 

363 

237 

243 

177 

183 

141 

147 

117 

123 

101 

107 

87 

93 

1444 

ooo 

144(5 

359 

365 

237 

243 

177 

1  83 

141 

147 

117 

123 

101 

107 

87 

93 

1446 

CM) 

1448 

359 

365 

239 

245 

177 

183 

141 

147 

117 

123 

101 

107 

87 

93 

1448 

CM) 

1450 

359 

365 

239 

245 

179 

185 

141 

147 

117 

123 

•101 

107 

87 

93 

1450 

ooo 

1452 

359 

365 

239 

245 

179 

185 

143 

149 

117 

123 

101 

107 

87 

93 

1452 

CM) 

1454 

361 

367 

239 

245 

179 

1  85 

143 

149 

111) 

125 

101 

107 

87 

93 

1454 

CM) 

1456 

361 

367 

239 

245 

179 

185 

143 

1  49 

119 

125 

101 

107 

87 

93 

1456 

ooo 

1458 

361 

367 

239 

245 

179 

185 

143 

149 

119 

125 

101 

107 

89 

95 

1458 

CM) 

1460 

361 

367 

241 

247 

179 

185 

143 

149 

119 

125 

101 

107 

89 

95 

1460 

(M) 

1462 

363 

369 

241 

247 

JL79 

185 

143 

149 

119 

125 

101 

107 

89 

95 

1462 

ooo 

1464 

363 

369 

211 

247 

179 

185 

.143 

149 

119 

125 

101 

107 

89 

95 

1464 

CM) 

1466 

363 

369 

241 

247 

1S1 

187 

143 

149 

119 

125 

101 

107 

89 

95 

1466 

CM) 

1468 

363 

369 

241 

247 

181 

187 

143 

149 

119 

125 

101 

107 

89 

95 

1468 

000 

1470 

365 

371 

2tl 

247 

181 

187 

143 

1  49 

119 

125 

101 

107 

89 

95 

1470 

CM> 

1472 

365 

371 

243 

249 

181 

187 

145 

151 

119 

125 

103 

109 

89 

95 

1472 

CM) 

1474 

365 

371 

243 

219 

181 

187 

145 

151 

119 

125 

103 

109 

89 

95 

1474 

ooo 

1476 

365 

371 

243 

249 

181 

187 

145 

151 

119 

125 

103 

109 

89 

95 

1476 

Caa) 

1478 

367 

373 

243 

U?49 

181 

187 

145 

151 

121 

127 

103 

109 

89 

95 

1478 

CM) 

14SO 

367 

373 

243 

249 

181 

187 

145 

151 

121 

127 

103 

109 

89 

95 

1480 

ooo 

1482 

367 

373 

243 

249 

183 

189 

145 

151 

121 

127 

103 

109 

89 

95 

1482 

CM) 

1484 

367 

373 

245 

251 

183 

189 

145 

151 

121 

127 

103 

109 

89 

95 

1484 

CM) 

1486 

369 

375 

245 

251 

183 

189 

145 

151 

121 

127 

103 

109 

89 

95 

1486 

ooo 

1488 

369 

375 

245 

251 

183 

189 

145 

151 

121 

127 

103 

109 

89 

95 

1488 

CM) 

1490 

369 

375 

245 

251 

183 

189 

145 

151 

121 

127 

103 

109 

91 

97 

1490 

CM) 

1492 

369 

375 

215 

251 

183 

189 

147 

153 

121 

127 

103 

109 

91 

97 

1492 

ooo 

1494 

371 

377 

245 

251 

183 

189 

147 

153 

121 

127 

103 

109 

91 

97 

1494 

(9«> 

1496 

371 

377 

247 

253 

183 

189 

147 

153 

121 

127 

103 

109 

91 

97 

1496 

C5a> 

1498 

371 

377 

247 

253 

isr, 

191 

147 

153 

121 

127 

103 

109 

91 

97 

1498 

ooo 

1500 

371 

377 

247 

253 

185 

191 

147 

153 

121 

127 

105 

111 

91 

97 

1500 

Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute 
magnitude  of  average  pitch  may  be  varied  within  reasonable  limits. 

MULTIPLE-CIRCUIT,  TRIPLE  WINDINGS,  FOR  DRUM  ARMATURES. 

RE-ENTRANCY 

No.  OF  CONDUCTORS 

FRONT  AND  BACK  PITCHES 

CO 

o: 

0 

4 
POLES 

6 

POLES 

8 
POLES 

10 

POLES 

12 

POLES 

14 

POLES 

16 

POLES 

CONDUC^ 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

F 

B 

O 
6 

Z 

(22) 

1502 

373 

379 

247 

253 

185 

191 

147 

1  5:< 

123 

129 

105 

111 

91 

97 

1502 

(22) 

1504 

373 

379 

247 

253 

185 

191 

147 

153 

123 

129 

105 

111 

91 

1)7 

1501 

ooo 

151  10 

373 

379 

247 

253 

185 

11)1 

147 

153 

123 

129 

105 

111 

91 

97 

1506 

(sa) 

1508 

373 

379 

249 

255 

185 

191 

147 

153 

123 

129 

105 

111 

91 

97 

1508 

(22) 

1510 

375 

381 

249 

255 

185 

11)1 

147 

153 

123 

12!) 

105 

111 

91 

97 

1510 

ooo 

1512 

375 

381 

249 

255 

185 

191 

149 

155 

123 

42!) 

105 

111 

91 

97 

1512 

(22) 

1514 

375 

381 

249 

•255 

187 

193 

149 

155 

123 

129 

105 

111 

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Above  choice  of  Pitches  will  prove  most  satisfactory,  although,  as  stated  in  text,  the  absolute 
magnitude  of  average  pitch  may  be  varied  within  reasonable  limfts. 

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(4) 


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of  Dynamos  and  Motors,  and  useful  Tables  of  Wire  Gauges.  Illustrated.  8vo,  cloth.  $2.50. 

TUMLIRZ,  Dr.  Potential,  and  its  Application  to  the  Explanation  of  Electrical  Phenomena.  Trans- 
lated by  D.  Robertson,  M.D.  12mo,  cloth.  11.25. 

TUNZELMANN,  G.  W.  de.     Electricity  in  Modern  Life.     Illustrated.     12mo,  cloth.     $1.25. 

URQUHART,  J.  W.  Dynamo  Construction.  A  Practical  Handbook  for  the  Use  of  Engineer  Constructors 
and  Electricians  in  Charge.  Illustrated.  12mo,  cloth.  $3.00. 

WALKER,  FREDERICK.  Practical  Dynamo  Building  for  Amateurs.  How  to  Wind  for  any  Output. 
Illustrated,  liiino,  cloth.  (No.  98  Van  Nostrand's  Science  Series.)  50  cents. 

WALMSLEY,  R.  M.  The  Electric  Current.  How  Produced  and  How  Used.  With  379  Illustrations. 
12iiu>,  cloth.  83.00. 

WEBB,  H.  L.  A  Practical  Guide  to  the  Testing  of  Insulated  Wires  and  Cables.  Illustrated.  12mo, 
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AVORMELL,  R.     Electricity  in  the  Service  of  Man.     A   Popular  and  Practical  Treatise  on  the  Applica- 
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K.  Wormell,  and  an  Introduction  by  Prof.   J.  Perry.     With  nearly  850  Illustrations.     Royal  8vo, 
cloth.     $6.00. 

WE Y MOUTH,  F.  MARTEN.  Drum  Armatures  and  Commutators.  (Theory  and  Practice.)  A  com- 
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Return  to  desk  from  which  borrowed. 
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OCT  2  1  1950 


LD  21-:OOm-9,'48(B399sl6)476 


